diff mbox series

[BTTV,FSL,P50x0,PASEMI] TV Time doesn't work anymore after dropping the overlay support

Message ID cb82b6c1-035c-cc6b-2843-6b87ed6315ac@xenosoft.de (mailing list archive)
State New, archived
Headers show
Series [BTTV,FSL,P50x0,PASEMI] TV Time doesn't work anymore after dropping the overlay support | expand

Commit Message

Christian Zigotzky May 1, 2023, 3:20 p.m. UTC
Hello,

I created a patch for adding overlay support again. TV Time works 
without any problems again. [1]

Please find attached the patch for adding the removed overlay support 
back for BTTV cards.

Cheers,
Christian

[1]
- https://i.ibb.co/6NJmj1y/Kernel-6-4-alpha1-Power-PC.png
- https://i.ibb.co/7rx0MyD/Kernel-6-4-alpha2-Power-PC.png


On 26 April 2023 at 04:09 pm, Christian Zigotzky wrote:
> Hello,
>
> TV Time doesn't work anymore on my Cyrus+ board with a FSL P50x0 
> PowerPC SoC [1] and on my P.A. Semi Nemo board [2] after dropping the 
> overlay support [3]. It starts and then the whole computer freezes.
>
> I use the following BTTV cards.
>
> - WinTV Express with a BT878A chip
> - Typhoon TView RDS + FM Stereo (BT878 chip)
>
> It would be really nice if we could get the overlay support back, 
> because we love TV Time. [4]
>
> We use TV Time with connected TV receivers and game consoles.
>
> Thanks,
> Christian
>
> [1] http://wiki.amiga.org/index.php?title=X5000
> [2] https://en.wikipedia.org/wiki/AmigaOne_X1000
> [3] 
> https://patchwork.kernel.org/project/linux-media/patch/20230302125731.1124945-4-hverkuil-cisco@xs4all.nl/
> [4] https://tvtime.sourceforge.net/

Comments

Hans Verkuil May 2, 2023, 6:57 a.m. UTC | #1
Hi Christian,

On 01/05/2023 17:20, Christian Zigotzky wrote:
> Hello,
> 
> I created a patch for adding overlay support again. TV Time works without any problems again. [1]
> 
> Please find attached the patch for adding the removed overlay support back for BTTV cards.
> 
> Cheers,
> Christian
> 
> [1]
> - https://i.ibb.co/6NJmj1y/Kernel-6-4-alpha1-Power-PC.png
> - https://i.ibb.co/7rx0MyD/Kernel-6-4-alpha2-Power-PC.png
> 
> 
> On 26 April 2023 at 04:09 pm, Christian Zigotzky wrote:
>> Hello,
>>
>> TV Time doesn't work anymore on my Cyrus+ board with a FSL P50x0 PowerPC SoC [1] and on my P.A. Semi Nemo board [2] after dropping the overlay support [3]. It starts and then the whole computer
>> freezes.

I really don't want to put destructive overlay support back, it should not
be necessary. On an intel processor tvtime with bttv without overlay works
fine, so why doesn't it for these boards?

I wonder if it is a big vs little endian issue that crops up when there is
no overlay. At least, I assume these two boards are big endian?

Can you try to use v4l2-ctl to stream from bttv? E.g.: v4l2-ctl -d /dev/video0 --stream-mmap

If that works (note that this just captures without showing the output), then
the issue is likely with tvtime, not bttv. If v4l2-ctl fails, then try again
after applying this series:

https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/

If it still fails, then there is likely a big endian problem in the bttv
driver that will need to be resolved.

If it is tvtime, then run with --verbose: hopefully that will give an indication
of which output driver it uses (Xv, DirectFB or SDL are the more likely candidates).

Note that I see no overlay support in the official tvtime repo:
https://git.linuxtv.org/tvtime.git/

It could be an output library that is handling that, though. But I need to know
how it is set up on the boards you use.

Regards,

	Hans

>>
>> I use the following BTTV cards.
>>
>> - WinTV Express with a BT878A chip
>> - Typhoon TView RDS + FM Stereo (BT878 chip)
>>
>> It would be really nice if we could get the overlay support back, because we love TV Time. [4]
>>
>> We use TV Time with connected TV receivers and game consoles.
>>
>> Thanks,
>> Christian
>>
>> [1] http://wiki.amiga.org/index.php?title=X5000
>> [2] https://en.wikipedia.org/wiki/AmigaOne_X1000
>> [3] https://patchwork.kernel.org/project/linux-media/patch/20230302125731.1124945-4-hverkuil-cisco@xs4all.nl/
>> [4] https://tvtime.sourceforge.net/
Christian Zigotzky May 5, 2023, 6:25 a.m. UTC | #2
On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
> If v4l2-ctl fails, then try again
> after applying this series:
>
> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
Your patch series solved the issue. Thanks a lot!
Hans Verkuil May 5, 2023, 6:45 a.m. UTC | #3
On 05/05/2023 08:25, Christian Zigotzky wrote:
> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>> If v4l2-ctl fails, then try again
>> after applying this series:
>>
>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
> Your patch series solved the issue. Thanks a lot!

Nice, but somewhat unexpected :-)

I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
support, but it won't have this series yet, that's for 6.5. But that would make 6.4
unusable for you.

I might have to revert the overlay removal, at least for bttv.

Regards,

	Hans
Christian Zigotzky May 5, 2023, 7:20 a.m. UTC | #4
On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
> On 05/05/2023 08:25, Christian Zigotzky wrote:
>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>> If v4l2-ctl fails, then try again
>>> after applying this series:
>>>
>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
>> Your patch series solved the issue. Thanks a lot!
> Nice, but somewhat unexpected :-)
>
> I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
> support, but it won't have this series yet, that's for 6.5. But that would make 6.4
> unusable for you.
>
> I might have to revert the overlay removal, at least for bttv.
>
> Regards,
>
> 	Hans
Hans,

You don't need to revert the overlay removal because your patch series 
work with the latest git kernel (6.4).

Thanks for your help,

Christian
Christian Zigotzky Sept. 4, 2023, 11:51 a.m. UTC | #5
On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
>> On 05/05/2023 08:25, Christian Zigotzky wrote:
>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>>> If v4l2-ctl fails, then try again
>>>> after applying this series:
>>>>
>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/ 
>>>>
>>> Your patch series solved the issue. Thanks a lot!
>> Nice, but somewhat unexpected :-)
>>
>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove 
>> destructive overlay
>> support, but it won't have this series yet, that's for 6.5. But that 
>> would make 6.4
>> unusable for you.
>>
>> I might have to revert the overlay removal, at least for bttv.
>>
>> Regards,
>>
>>     Hans
> Hans,
>
> You don't need to revert the overlay removal because your patch series 
> work with the latest git kernel (6.4).
>
> Thanks for your help,
>
> Christian

Hello Hans,

I successfully used your patches for the kernel 6.5. Everything works 
without any problems with your patch series from May.

Your patches have been added with the latest Media updates [1] for the 
kernel 6.6.

The patches works but I have a green bar in the bottum of the window if 
I use the composite input. [2]

I don't have this green bar with your May patch series.

Could you please check your latest patches?

Thanks,

Christian

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
[2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
Christian Zigotzky Sept. 4, 2023, 12:02 p.m. UTC | #6
On 04 September 2023 at 01:51 pm, Christian Zigotzky wrote:
> On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
>> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
>>> On 05/05/2023 08:25, Christian Zigotzky wrote:
>>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>>>> If v4l2-ctl fails, then try again
>>>>> after applying this series:
>>>>>
>>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/ 
>>>>>
>>>> Your patch series solved the issue. Thanks a lot!
>>> Nice, but somewhat unexpected :-)
>>>
>>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove 
>>> destructive overlay
>>> support, but it won't have this series yet, that's for 6.5. But that 
>>> would make 6.4
>>> unusable for you.
>>>
>>> I might have to revert the overlay removal, at least for bttv.
>>>
>>> Regards,
>>>
>>>     Hans
>> Hans,
>>
>> You don't need to revert the overlay removal because your patch 
>> series work with the latest git kernel (6.4).
>>
>> Thanks for your help,
>>
>> Christian
>
> Hello Hans,
>
> I successfully used your patches for the kernel 6.5. Everything works 
> without any problems with your patch series from May.
>
> Your patches have been added with the latest Media updates [1] for the 
> kernel 6.6.
>
> The patches work but I have a green bar in the bottum of the window if 
> I use the composite input. [2]
>
> I don't have this green bar with your May patch series.
>
> Could you please check your latest patches?
>
> Thanks,
>
> Christian
>
> [1] 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
> [2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
>
>
I tested with two bttv TV cards.

- Typhoon TView RDS + FM Stereo (BT878 chip)
- WinTV Express (BT878A chip)

I have this issue with both TV cards if I use the composite input.
Hans Verkuil Sept. 7, 2023, 3:23 p.m. UTC | #7
Hi Deb,

On 04/09/2023 13:51, Christian Zigotzky wrote:
> On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
>> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
>>> On 05/05/2023 08:25, Christian Zigotzky wrote:
>>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>>>> If v4l2-ctl fails, then try again
>>>>> after applying this series:
>>>>>
>>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
>>>> Your patch series solved the issue. Thanks a lot!
>>> Nice, but somewhat unexpected :-)
>>>
>>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
>>> support, but it won't have this series yet, that's for 6.5. But that would make 6.4
>>> unusable for you.
>>>
>>> I might have to revert the overlay removal, at least for bttv.
>>>
>>> Regards,
>>>
>>>     Hans
>> Hans,
>>
>> You don't need to revert the overlay removal because your patch series work with the latest git kernel (6.4).
>>
>> Thanks for your help,
>>
>> Christian
> 
> Hello Hans,
> 
> I successfully used your patches for the kernel 6.5. Everything works without any problems with your patch series from May.
> 
> Your patches have been added with the latest Media updates [1] for the kernel 6.6.
> 
> The patches works but I have a green bar in the bottum of the window if I use the composite input. [2]
> 
> I don't have this green bar with your May patch series.
> 
> Could you please check your latest patches?
> 
> Thanks,
> 
> Christian
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
> [2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
> 
> 

After some testing and debugging I found this change in the bttv vb2 conversion
patch:

https://patchwork.linuxtv.org/project/linux-media/patch/d785cd8b0d8c19c05fcaa1536622e2fdd9f8ede3.1689379982.git.deborah.brouwer@collabora.com/

> diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
> index 3e0dac56de54..436baf6c8b08 100644
> --- a/drivers/media/pci/bt8xx/bttv-risc.c
> +++ b/drivers/media/pci/bt8xx/bttv-risc.c
> @@ -67,8 +67,10 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
>  	/* scan lines */
>  	sg = sglist;
>  	for (line = 0; line < store_lines; line++) {
> -		if ((btv->opt_vcr_hack) &&
> -		    (line >= (store_lines - VCR_HACK_LINES)))
> +		if ((line >= (store_lines - VCR_HACK_LINES)) &&
> +		    (btv->opt_vcr_hack ||
> +		    (V4L2_FIELD_HAS_BOTH(btv->field) ||
> +		     btv->field == V4L2_FIELD_ALTERNATE)))
>  			continue;
>  		while (offset && offset >= sg_dma_len(sg)) {
>  			offset -= sg_dma_len(sg);

It is this change that causes the issue: basically the condition
(V4L2_FIELD_HAS_BOTH(btv->field) || btv->field == V4L2_FIELD_ALTERNATE)
is almost always true (it is only false for FIELD_TOP/BOTTOM), so it is
as if vcr_hack is always turned on.

It looks to me like some debug code accidentally ended up in this patch.
Reverting this change makes everything look good again (Christian, it would
be great if you can confirm that this also fixes the issue for you!).

Deb, can you remember anything about this change?

Regards,

	Hans
Christian Zigotzky Sept. 7, 2023, 3:49 p.m. UTC | #8
> On 7. Sep 2023, at 17:23, Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
> 
> Hi Deb,
> 
>> On 04/09/2023 13:51, Christian Zigotzky wrote:
>>> On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
>>> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
>>>> On 05/05/2023 08:25, Christian Zigotzky wrote:
>>>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>>>>> If v4l2-ctl fails, then try again
>>>>>> after applying this series:
>>>>>> 
>>>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
>>>>> Your patch series solved the issue. Thanks a lot!
>>>> Nice, but somewhat unexpected :-)
>>>> 
>>>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
>>>> support, but it won't have this series yet, that's for 6.5. But that would make 6.4
>>>> unusable for you.
>>>> 
>>>> I might have to revert the overlay removal, at least for bttv.
>>>> 
>>>> Regards,
>>>> 
>>>>     Hans
>>> Hans,
>>> 
>>> You don't need to revert the overlay removal because your patch series work with the latest git kernel (6.4).
>>> 
>>> Thanks for your help,
>>> 
>>> Christian
>> 
>> Hello Hans,
>> 
>> I successfully used your patches for the kernel 6.5. Everything works without any problems with your patch series from May.
>> 
>> Your patches have been added with the latest Media updates [1] for the kernel 6.6.
>> 
>> The patches works but I have a green bar in the bottum of the window if I use the composite input. [2]
>> 
>> I don't have this green bar with your May patch series.
>> 
>> Could you please check your latest patches?
>> 
>> Thanks,
>> 
>> Christian
>> 
>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
>> [2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
>> 
>> 
> 
> After some testing and debugging I found this change in the bttv vb2 conversion
> patch:
> 
> https://patchwork.linuxtv.org/project/linux-media/patch/d785cd8b0d8c19c05fcaa1536622e2fdd9f8ede3.1689379982.git.deborah.brouwer@collabora.com/
> 
>> diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
>> index 3e0dac56de54..436baf6c8b08 100644
>> --- a/drivers/media/pci/bt8xx/bttv-risc.c
>> +++ b/drivers/media/pci/bt8xx/bttv-risc.c
>> @@ -67,8 +67,10 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
>>    /* scan lines */
>>    sg = sglist;
>>    for (line = 0; line < store_lines; line++) {
>> -        if ((btv->opt_vcr_hack) &&
>> -            (line >= (store_lines - VCR_HACK_LINES)))
>> +        if ((line >= (store_lines - VCR_HACK_LINES)) &&
>> +            (btv->opt_vcr_hack ||
>> +            (V4L2_FIELD_HAS_BOTH(btv->field) ||
>> +             btv->field == V4L2_FIELD_ALTERNATE)))
>>            continue;
>>        while (offset && offset >= sg_dma_len(sg)) {
>>            offset -= sg_dma_len(sg);
> 
> It is this change that causes the issue: basically the condition
> (V4L2_FIELD_HAS_BOTH(btv->field) || btv->field == V4L2_FIELD_ALTERNATE)
> is almost always true (it is only false for FIELD_TOP/BOTTOM), so it is
> as if vcr_hack is always turned on.
> 
> It looks to me like some debug code accidentally ended up in this patch.
> Reverting this change makes everything look good again (Christian, it would
> be great if you can confirm that this also fixes the issue for you!).
> 
> Deb, can you remember anything about this change?
> 
> Regards,
> 
>    Hans
> 
> 
Hi Hans,

Thanks a lot for your answer.  I will test it as soon as possible.

It’s great, that you support the BTTV driver for old TV cards.

Have a nice day.

Cheers,
Christian
Deborah Brouwer Sept. 10, 2023, 2:33 a.m. UTC | #9
On Thu, Sep 7, 2023 at 8:23 AM Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>
> Hi Deb,
>
> On 04/09/2023 13:51, Christian Zigotzky wrote:
> > On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
> >> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
> >>> On 05/05/2023 08:25, Christian Zigotzky wrote:
> >>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
> >>>>> If v4l2-ctl fails, then try again
> >>>>> after applying this series:
> >>>>>
> >>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
> >>>> Your patch series solved the issue. Thanks a lot!
> >>> Nice, but somewhat unexpected :-)
> >>>
> >>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
> >>> support, but it won't have this series yet, that's for 6.5. But that would make 6.4
> >>> unusable for you.
> >>>
> >>> I might have to revert the overlay removal, at least for bttv.
> >>>
> >>> Regards,
> >>>
> >>>     Hans
> >> Hans,
> >>
> >> You don't need to revert the overlay removal because your patch series work with the latest git kernel (6.4).
> >>
> >> Thanks for your help,
> >>
> >> Christian
> >
> > Hello Hans,
> >
> > I successfully used your patches for the kernel 6.5. Everything works without any problems with your patch series from May.
> >
> > Your patches have been added with the latest Media updates [1] for the kernel 6.6.
> >
> > The patches works but I have a green bar in the bottum of the window if I use the composite input. [2]
> >
> > I don't have this green bar with your May patch series.
> >
> > Could you please check your latest patches?
> >
> > Thanks,
> >
> > Christian
> >
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
> > [2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
> >
> >
>
> After some testing and debugging I found this change in the bttv vb2 conversion
> patch:
>
> https://patchwork.linuxtv.org/project/linux-media/patch/d785cd8b0d8c19c05fcaa1536622e2fdd9f8ede3.1689379982.git.deborah.brouwer@collabora.com/
>
> > diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
> > index 3e0dac56de54..436baf6c8b08 100644
> > --- a/drivers/media/pci/bt8xx/bttv-risc.c
> > +++ b/drivers/media/pci/bt8xx/bttv-risc.c
> > @@ -67,8 +67,10 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
> >       /* scan lines */
> >       sg = sglist;
> >       for (line = 0; line < store_lines; line++) {
> > -             if ((btv->opt_vcr_hack) &&
> > -                 (line >= (store_lines - VCR_HACK_LINES)))
> > +             if ((line >= (store_lines - VCR_HACK_LINES)) &&
> > +                 (btv->opt_vcr_hack ||
> > +                 (V4L2_FIELD_HAS_BOTH(btv->field) ||
> > +                  btv->field == V4L2_FIELD_ALTERNATE)))
> >                       continue;
> >               while (offset && offset >= sg_dma_len(sg)) {
> >                       offset -= sg_dma_len(sg);
>
> It is this change that causes the issue: basically the condition
> (V4L2_FIELD_HAS_BOTH(btv->field) || btv->field == V4L2_FIELD_ALTERNATE)
> is almost always true (it is only false for FIELD_TOP/BOTTOM), so it is
> as if vcr_hack is always turned on.
>
> It looks to me like some debug code accidentally ended up in this patch.
> Reverting this change makes everything look good again (Christian, it would
> be great if you can confirm that this also fixes the issue for you!).
>
> Deb, can you remember anything about this change?

This is not debug code.  I made the change to fix the latency and
frame drop issues
that were otherwise occurring with vb2; as I said in the cover letter to v3:

"- remove the last four lines in interlaced,
sequential top/bottom, and alternating buffers
to prevent long latency and frame drops
(this is instead of just enabling the existing
VCR hack by default);"
https://lore.kernel.org/linux-media/cover.1689379982.git.deborah.brouwer@collabora.com/

However, if your testing shows that it isn't needed, then it would be
fine to remove this
code and just let the user enable the "vcr hack" as needed.  This was
my original approach
in v2, but I thought you had said at the time that you were seeing
massive framedrops in v2?

I didn't notice this green line before because I was testing in qv4l2
with the default
Pixel Format  : 'BGR3' (24-bit BGR 8-8-8) whereas tvtime is using
YUYV' (YUYV 4:2:2)

One fix that worked for me was to adjust the "OverScan" configuration in tvtime
so that it is at least 3.5.  The /etc/tvtime/tvtime.xml configuration
file recommends
even higher at 8.0.  Christian, please try adjusting the overscan
value to see if
that is a possible solution as well.

Thanks,
Deb

>
> Regards,
>
>         Hans
>
>
>
Hans Verkuil Sept. 11, 2023, 9:51 a.m. UTC | #10
Hi Deb,

On 10/09/2023 04:33, Deborah Brouwer wrote:
> On Thu, Sep 7, 2023 at 8:23 AM Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>>
>> Hi Deb,
>>
>> On 04/09/2023 13:51, Christian Zigotzky wrote:
>>> On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
>>>> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
>>>>> On 05/05/2023 08:25, Christian Zigotzky wrote:
>>>>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>>>>>> If v4l2-ctl fails, then try again
>>>>>>> after applying this series:
>>>>>>>
>>>>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
>>>>>> Your patch series solved the issue. Thanks a lot!
>>>>> Nice, but somewhat unexpected :-)
>>>>>
>>>>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
>>>>> support, but it won't have this series yet, that's for 6.5. But that would make 6.4
>>>>> unusable for you.
>>>>>
>>>>> I might have to revert the overlay removal, at least for bttv.
>>>>>
>>>>> Regards,
>>>>>
>>>>>     Hans
>>>> Hans,
>>>>
>>>> You don't need to revert the overlay removal because your patch series work with the latest git kernel (6.4).
>>>>
>>>> Thanks for your help,
>>>>
>>>> Christian
>>>
>>> Hello Hans,
>>>
>>> I successfully used your patches for the kernel 6.5. Everything works without any problems with your patch series from May.
>>>
>>> Your patches have been added with the latest Media updates [1] for the kernel 6.6.
>>>
>>> The patches works but I have a green bar in the bottum of the window if I use the composite input. [2]
>>>
>>> I don't have this green bar with your May patch series.
>>>
>>> Could you please check your latest patches?
>>>
>>> Thanks,
>>>
>>> Christian
>>>
>>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
>>> [2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
>>>
>>>
>>
>> After some testing and debugging I found this change in the bttv vb2 conversion
>> patch:
>>
>> https://patchwork.linuxtv.org/project/linux-media/patch/d785cd8b0d8c19c05fcaa1536622e2fdd9f8ede3.1689379982.git.deborah.brouwer@collabora.com/
>>
>>> diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
>>> index 3e0dac56de54..436baf6c8b08 100644
>>> --- a/drivers/media/pci/bt8xx/bttv-risc.c
>>> +++ b/drivers/media/pci/bt8xx/bttv-risc.c
>>> @@ -67,8 +67,10 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
>>>       /* scan lines */
>>>       sg = sglist;
>>>       for (line = 0; line < store_lines; line++) {
>>> -             if ((btv->opt_vcr_hack) &&
>>> -                 (line >= (store_lines - VCR_HACK_LINES)))
>>> +             if ((line >= (store_lines - VCR_HACK_LINES)) &&
>>> +                 (btv->opt_vcr_hack ||
>>> +                 (V4L2_FIELD_HAS_BOTH(btv->field) ||
>>> +                  btv->field == V4L2_FIELD_ALTERNATE)))
>>>                       continue;
>>>               while (offset && offset >= sg_dma_len(sg)) {
>>>                       offset -= sg_dma_len(sg);
>>
>> It is this change that causes the issue: basically the condition
>> (V4L2_FIELD_HAS_BOTH(btv->field) || btv->field == V4L2_FIELD_ALTERNATE)
>> is almost always true (it is only false for FIELD_TOP/BOTTOM), so it is
>> as if vcr_hack is always turned on.
>>
>> It looks to me like some debug code accidentally ended up in this patch.
>> Reverting this change makes everything look good again (Christian, it would
>> be great if you can confirm that this also fixes the issue for you!).
>>
>> Deb, can you remember anything about this change?
> 
> This is not debug code.  I made the change to fix the latency and
> frame drop issues
> that were otherwise occurring with vb2; as I said in the cover letter to v3:
> 
> "- remove the last four lines in interlaced,
> sequential top/bottom, and alternating buffers
> to prevent long latency and frame drops
> (this is instead of just enabling the existing
> VCR hack by default);"
> https://lore.kernel.org/linux-media/cover.1689379982.git.deborah.brouwer@collabora.com/
> 
> However, if your testing shows that it isn't needed, then it would be
> fine to remove this
> code and just let the user enable the "vcr hack" as needed.  This was
> my original approach
> in v2, but I thought you had said at the time that you were seeing
> massive framedrops in v2?

That's not quite what I said:

"Another thing I discovered is that for PAL the vcr_hack control has to be enabled,
otherwise the video is full of glitches. This was present before your series, and
happens even with a video signal from a proper PAL video generator, so this is really
strange. I can't remember that I needed this in the past, but it has been years
since I last tested it.

PAL capture is fine for Top/Bottom/Alternate settings, it only fails for Interlaced
and Sequential Top/Bottom capture modes."

This issue was present before your series, so this is not something that should be
changed in a vb2 conversion, since this has nothing to do with it.

In addition, it is a PAL only issue, and this change would turn on vcr_hack for NTSC
as well, and also for FIELD_ALTERNATE, even though that is not affected by it.

Interestingly, since I was wondering why Christian didn't see it even though he is
in a PAL country, I tested with tvtime and that displays it fine, but qv4l2/qvidcap
show the glitches. This suggests that it is a problem in those utils, and not in the
driver. I'll dig deeper into this.

In the meantime, I'll prepare a patch reverting this change for v6.6.

Regards,

	Hans

> 
> I didn't notice this green line before because I was testing in qv4l2
> with the default
> Pixel Format  : 'BGR3' (24-bit BGR 8-8-8) whereas tvtime is using
> YUYV' (YUYV 4:2:2)
> 
> One fix that worked for me was to adjust the "OverScan" configuration in tvtime
> so that it is at least 3.5.  The /etc/tvtime/tvtime.xml configuration
> file recommends
> even higher at 8.0.  Christian, please try adjusting the overscan
> value to see if
> that is a possible solution as well.
> 
> Thanks,
> Deb
> 
>>
>> Regards,
>>
>>         Hans
>>
>>
>>
Hans Verkuil Sept. 14, 2023, 7:01 a.m. UTC | #11
On 11/09/2023 11:51, Hans Verkuil wrote:
> Hi Deb,
> 
> On 10/09/2023 04:33, Deborah Brouwer wrote:
>> On Thu, Sep 7, 2023 at 8:23 AM Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>>>
>>> Hi Deb,
>>>
>>> On 04/09/2023 13:51, Christian Zigotzky wrote:
>>>> On 05 May 2023 at 09:20 am, Christian Zigotzky wrote:
>>>>> On 05 May 2023 at 08:45 am, Hans Verkuil wrote:
>>>>>> On 05/05/2023 08:25, Christian Zigotzky wrote:
>>>>>>> On 02 May 2023 at 08:57 am, Hans Verkuil wrote:
>>>>>>>> If v4l2-ctl fails, then try again
>>>>>>>> after applying this series:
>>>>>>>>
>>>>>>>> https://patchwork.linuxtv.org/project/linux-media/cover/cover.1682995256.git.deborah.brouwer@collabora.com/
>>>>>>> Your patch series solved the issue. Thanks a lot!
>>>>>> Nice, but somewhat unexpected :-)
>>>>>>
>>>>>> I'm a little bit unsure how to proceed: the 6.4 kernel will remove destructive overlay
>>>>>> support, but it won't have this series yet, that's for 6.5. But that would make 6.4
>>>>>> unusable for you.
>>>>>>
>>>>>> I might have to revert the overlay removal, at least for bttv.
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>>     Hans
>>>>> Hans,
>>>>>
>>>>> You don't need to revert the overlay removal because your patch series work with the latest git kernel (6.4).
>>>>>
>>>>> Thanks for your help,
>>>>>
>>>>> Christian
>>>>
>>>> Hello Hans,
>>>>
>>>> I successfully used your patches for the kernel 6.5. Everything works without any problems with your patch series from May.
>>>>
>>>> Your patches have been added with the latest Media updates [1] for the kernel 6.6.
>>>>
>>>> The patches works but I have a green bar in the bottum of the window if I use the composite input. [2]
>>>>
>>>> I don't have this green bar with your May patch series.
>>>>
>>>> Could you please check your latest patches?
>>>>
>>>> Thanks,
>>>>
>>>> Christian
>>>>
>>>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=307d59039fb26212a84a9aa6a134a7d2bdea34ca
>>>> [2] https://i.ibb.co/D4K6j2c/Kernel-6-6-alpha2-Power-PC.png
>>>>
>>>>
>>>
>>> After some testing and debugging I found this change in the bttv vb2 conversion
>>> patch:
>>>
>>> https://patchwork.linuxtv.org/project/linux-media/patch/d785cd8b0d8c19c05fcaa1536622e2fdd9f8ede3.1689379982.git.deborah.brouwer@collabora.com/
>>>
>>>> diff --git a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
>>>> index 3e0dac56de54..436baf6c8b08 100644
>>>> --- a/drivers/media/pci/bt8xx/bttv-risc.c
>>>> +++ b/drivers/media/pci/bt8xx/bttv-risc.c
>>>> @@ -67,8 +67,10 @@ bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
>>>>       /* scan lines */
>>>>       sg = sglist;
>>>>       for (line = 0; line < store_lines; line++) {
>>>> -             if ((btv->opt_vcr_hack) &&
>>>> -                 (line >= (store_lines - VCR_HACK_LINES)))
>>>> +             if ((line >= (store_lines - VCR_HACK_LINES)) &&
>>>> +                 (btv->opt_vcr_hack ||
>>>> +                 (V4L2_FIELD_HAS_BOTH(btv->field) ||
>>>> +                  btv->field == V4L2_FIELD_ALTERNATE)))
>>>>                       continue;
>>>>               while (offset && offset >= sg_dma_len(sg)) {
>>>>                       offset -= sg_dma_len(sg);
>>>
>>> It is this change that causes the issue: basically the condition
>>> (V4L2_FIELD_HAS_BOTH(btv->field) || btv->field == V4L2_FIELD_ALTERNATE)
>>> is almost always true (it is only false for FIELD_TOP/BOTTOM), so it is
>>> as if vcr_hack is always turned on.
>>>
>>> It looks to me like some debug code accidentally ended up in this patch.
>>> Reverting this change makes everything look good again (Christian, it would
>>> be great if you can confirm that this also fixes the issue for you!).
>>>
>>> Deb, can you remember anything about this change?
>>
>> This is not debug code.  I made the change to fix the latency and
>> frame drop issues
>> that were otherwise occurring with vb2; as I said in the cover letter to v3:
>>
>> "- remove the last four lines in interlaced,
>> sequential top/bottom, and alternating buffers
>> to prevent long latency and frame drops
>> (this is instead of just enabling the existing
>> VCR hack by default);"
>> https://lore.kernel.org/linux-media/cover.1689379982.git.deborah.brouwer@collabora.com/
>>
>> However, if your testing shows that it isn't needed, then it would be
>> fine to remove this
>> code and just let the user enable the "vcr hack" as needed.  This was
>> my original approach
>> in v2, but I thought you had said at the time that you were seeing
>> massive framedrops in v2?
> 
> That's not quite what I said:
> 
> "Another thing I discovered is that for PAL the vcr_hack control has to be enabled,
> otherwise the video is full of glitches. This was present before your series, and
> happens even with a video signal from a proper PAL video generator, so this is really
> strange. I can't remember that I needed this in the past, but it has been years
> since I last tested it.
> 
> PAL capture is fine for Top/Bottom/Alternate settings, it only fails for Interlaced
> and Sequential Top/Bottom capture modes."
> 
> This issue was present before your series, so this is not something that should be
> changed in a vb2 conversion, since this has nothing to do with it.
> 
> In addition, it is a PAL only issue, and this change would turn on vcr_hack for NTSC
> as well, and also for FIELD_ALTERNATE, even though that is not affected by it.
> 
> Interestingly, since I was wondering why Christian didn't see it even though he is
> in a PAL country, I tested with tvtime and that displays it fine, but qv4l2/qvidcap
> show the glitches. This suggests that it is a problem in those utils, and not in the
> driver. I'll dig deeper into this.

There is definitely something going on with qv4l2/qvidcap, although I have still not
been able to figure it out. Those two applications have very similar openGL shader code,
so I suspect it is related to that, but what exactly is going wrong there is not clear
to me.

Regards,

	Hans

> 
> In the meantime, I'll prepare a patch reverting this change for v6.6.
> 
> Regards,
> 
> 	Hans
> 
>>
>> I didn't notice this green line before because I was testing in qv4l2
>> with the default
>> Pixel Format  : 'BGR3' (24-bit BGR 8-8-8) whereas tvtime is using
>> YUYV' (YUYV 4:2:2)
>>
>> One fix that worked for me was to adjust the "OverScan" configuration in tvtime
>> so that it is at least 3.5.  The /etc/tvtime/tvtime.xml configuration
>> file recommends
>> even higher at 8.0.  Christian, please try adjusting the overscan
>> value to see if
>> that is a possible solution as well.
>>
>> Thanks,
>> Deb
>>
>>>
>>> Regards,
>>>
>>>         Hans
>>>
>>>
>>>
>
diff mbox series

Patch

diff -rupN a/drivers/media/pci/bt8xx/btcx-risc.c b/drivers/media/pci/bt8xx/btcx-risc.c
--- a/drivers/media/pci/bt8xx/btcx-risc.c	2023-04-27 04:46:15.574522003 +0200
+++ b/drivers/media/pci/bt8xx/btcx-risc.c	2023-04-27 04:45:43.011980514 +0200
@@ -75,3 +75,156 @@  int btcx_riscmem_alloc(struct pci_dev *p
 	}
 	return 0;
 }
+
+/* ---------------------------------------------------------- */
+/* screen overlay helpers                                     */
+
+int
+btcx_screen_clips(int swidth, int sheight, struct v4l2_rect *win,
+		  struct v4l2_clip *clips, unsigned int n)
+{
+	if (win->left < 0) {
+		/* left */
+		clips[n].c.left = 0;
+		clips[n].c.top = 0;
+		clips[n].c.width  = -win->left;
+		clips[n].c.height = win->height;
+		n++;
+	}
+	if (win->left + win->width > swidth) {
+		/* right */
+		clips[n].c.left   = swidth - win->left;
+		clips[n].c.top    = 0;
+		clips[n].c.width  = win->width - clips[n].c.left;
+		clips[n].c.height = win->height;
+		n++;
+	}
+	if (win->top < 0) {
+		/* top */
+		clips[n].c.left = 0;
+		clips[n].c.top = 0;
+		clips[n].c.width  = win->width;
+		clips[n].c.height = -win->top;
+		n++;
+	}
+	if (win->top + win->height > sheight) {
+		/* bottom */
+		clips[n].c.left = 0;
+		clips[n].c.top = sheight - win->top;
+		clips[n].c.width  = win->width;
+		clips[n].c.height = win->height - clips[n].c.top;
+		n++;
+	}
+	return n;
+}
+
+int
+btcx_align(struct v4l2_rect *win, struct v4l2_clip *clips, unsigned int n, int mask)
+{
+	s32 nx,nw,dx;
+	unsigned int i;
+
+	/* fixup window */
+	nx = (win->left + mask) & ~mask;
+	nw = (win->width) & ~mask;
+	if (nx + nw > win->left + win->width)
+		nw -= mask+1;
+	dx = nx - win->left;
+	win->left  = nx;
+	win->width = nw;
+	dprintk("btcx: window align %dx%d+%d+%d [dx=%d]\n",
+	       win->width, win->height, win->left, win->top, dx);
+
+	/* fixup clips */
+	for (i = 0; i < n; i++) {
+		nx = (clips[i].c.left-dx) & ~mask;
+		nw = (clips[i].c.width) & ~mask;
+		if (nx + nw < clips[i].c.left-dx + clips[i].c.width)
+			nw += mask+1;
+		clips[i].c.left  = nx;
+		clips[i].c.width = nw;
+		dprintk("btcx:   clip align %dx%d+%d+%d\n",
+		       clips[i].c.width, clips[i].c.height,
+		       clips[i].c.left, clips[i].c.top);
+	}
+	return 0;
+}
+
+void
+btcx_sort_clips(struct v4l2_clip *clips, unsigned int nclips)
+{
+	int i,j,n;
+
+	if (nclips < 2)
+		return;
+	for (i = nclips-2; i >= 0; i--) {
+		for (n = 0, j = 0; j <= i; j++) {
+			if (clips[j].c.left > clips[j+1].c.left) {
+				swap(clips[j], clips[j + 1]);
+				n++;
+			}
+		}
+		if (0 == n)
+			break;
+	}
+}
+
+void
+btcx_calc_skips(int line, int width, int *maxy,
+		struct btcx_skiplist *skips, unsigned int *nskips,
+		const struct v4l2_clip *clips, unsigned int nclips)
+{
+	unsigned int clip,skip;
+	int end, maxline;
+
+	skip=0;
+	maxline = 9999;
+	for (clip = 0; clip < nclips; clip++) {
+
+		/* sanity checks */
+		if (clips[clip].c.left + clips[clip].c.width <= 0)
+			continue;
+		if (clips[clip].c.left > (signed)width)
+			break;
+
+		/* vertical range */
+		if (line > clips[clip].c.top+clips[clip].c.height-1)
+			continue;
+		if (line < clips[clip].c.top) {
+			if (maxline > clips[clip].c.top-1)
+				maxline = clips[clip].c.top-1;
+			continue;
+		}
+		if (maxline > clips[clip].c.top+clips[clip].c.height-1)
+			maxline = clips[clip].c.top+clips[clip].c.height-1;
+
+		/* horizontal range */
+		if (0 == skip || clips[clip].c.left > skips[skip-1].end) {
+			/* new one */
+			skips[skip].start = clips[clip].c.left;
+			if (skips[skip].start < 0)
+				skips[skip].start = 0;
+			skips[skip].end = clips[clip].c.left + clips[clip].c.width;
+			if (skips[skip].end > width)
+				skips[skip].end = width;
+			skip++;
+		} else {
+			/* overlaps -- expand last one */
+			end = clips[clip].c.left + clips[clip].c.width;
+			if (skips[skip-1].end < end)
+				skips[skip-1].end = end;
+			if (skips[skip-1].end > width)
+				skips[skip-1].end = width;
+		}
+	}
+	*nskips = skip;
+	*maxy = maxline;
+
+	if (btcx_debug) {
+		dprintk("btcx: skips line %d-%d:", line, maxline);
+		for (skip = 0; skip < *nskips; skip++) {
+			pr_cont(" %d-%d", skips[skip].start, skips[skip].end);
+		}
+		pr_cont("\n");
+	}
+}
diff -rupN a/drivers/media/pci/bt8xx/btcx-risc.h b/drivers/media/pci/bt8xx/btcx-risc.h
--- a/drivers/media/pci/bt8xx/btcx-risc.h	2023-04-27 04:46:15.574522003 +0200
+++ b/drivers/media/pci/bt8xx/btcx-risc.h	2023-04-27 04:45:11.061431009 +0200
@@ -16,3 +16,12 @@  int  btcx_riscmem_alloc(struct pci_dev *
 			unsigned int size);
 void btcx_riscmem_free(struct pci_dev *pci,
 		       struct btcx_riscmem *risc);
+
+int btcx_screen_clips(int swidth, int sheight, struct v4l2_rect *win,
+		      struct v4l2_clip *clips, unsigned int n);
+int btcx_align(struct v4l2_rect *win, struct v4l2_clip *clips,
+	       unsigned int n, int mask);
+void btcx_sort_clips(struct v4l2_clip *clips, unsigned int nclips);
+void btcx_calc_skips(int line, int width, int *maxy,
+		     struct btcx_skiplist *skips, unsigned int *nskips,
+		     const struct v4l2_clip *clips, unsigned int nclips);
diff -rupN a/drivers/media/pci/bt8xx/bttv-cards.c b/drivers/media/pci/bt8xx/bttv-cards.c
--- a/drivers/media/pci/bt8xx/bttv-cards.c	2023-04-27 04:46:15.574522003 +0200
+++ b/drivers/media/pci/bt8xx/bttv-cards.c	2023-04-27 04:44:43.446820879 +0200
@@ -81,6 +81,7 @@  static int pvr_boot(struct bttv *btv);
 static unsigned int triton1;
 static unsigned int vsfx;
 static unsigned int latency = UNSET;
+int no_overlay=-1;
 
 static unsigned int card[BTTV_MAX]   = { [ 0 ... (BTTV_MAX-1) ] = UNSET };
 static unsigned int pll[BTTV_MAX]    = { [ 0 ... (BTTV_MAX-1) ] = UNSET };
@@ -98,6 +99,7 @@  static unsigned int audiomux[5] = { [ 0
 /* insmod options */
 module_param(triton1,    int, 0444);
 module_param(vsfx,       int, 0444);
+module_param(no_overlay, int, 0444);
 module_param(latency,    int, 0444);
 module_param(gpiomask,   int, 0444);
 module_param(audioall,   int, 0444);
@@ -125,6 +127,7 @@  MODULE_PARM_DESC(audiodev, "specify audi
 		"\t\t 2 = tda7432\n"
 		"\t\t 3 = tvaudio");
 MODULE_PARM_DESC(saa6588, "if 1, then load the saa6588 RDS module, default (0) is to use the card definition.");
+MODULE_PARM_DESC(no_overlay, "allow override overlay default (0 disables, 1 enables) [some VIA/SIS chipsets are known to have problem with overlay]");
 
 
 /* I2C addresses list */
@@ -4866,8 +4869,11 @@  static void gv800s_init(struct bttv *btv
 
 void __init bttv_check_chipset(void)
 {
+	int pcipci_fail = 0;
 	struct pci_dev *dev = NULL;
 
+	if (pci_pci_problems & (PCIPCI_FAIL|PCIAGP_FAIL))	/* should check if target is AGP */
+		pcipci_fail = 1;
 	if (pci_pci_problems & (PCIPCI_TRITON|PCIPCI_NATOMA|PCIPCI_VIAETBF))
 		triton1 = 1;
 	if (pci_pci_problems & PCIPCI_VSFX)
@@ -4883,6 +4889,15 @@  void __init bttv_check_chipset(void)
 		pr_info("Host bridge needs ETBF enabled\n");
 	if (vsfx)
 		pr_info("Host bridge needs VSFX enabled\n");
+	if (pcipci_fail) {
+		pr_info("bttv and your chipset may not work together\n");
+		if (!no_overlay) {
+			pr_info("overlay will be disabled\n");
+			no_overlay = 1;
+		} else {
+			pr_info("overlay forced. Use this option at your own risk.\n");
+		}
+	}
 	if (UNSET != latency)
 		pr_info("pci latency fixup [%d]\n", latency);
 	while ((dev = pci_get_device(PCI_VENDOR_ID_INTEL,
diff -rupN a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c
--- a/drivers/media/pci/bt8xx/bttv-driver.c	2023-04-27 04:46:15.574522003 +0200
+++ b/drivers/media/pci/bt8xx/bttv-driver.c	2023-04-27 04:44:23.737099449 +0200
@@ -49,6 +49,7 @@ 
 #include <media/i2c/saa6588.h>
 
 #define BTTV_VERSION "0.9.19"
+#define V4L2_FBUF_CAP_LIST_CLIPPING     0x0004
 
 unsigned int bttv_num;			/* number of Bt848s in use */
 struct bttv *bttvs[BTTV_MAX];
@@ -624,14 +625,20 @@  static const unsigned int FORMATS = ARRA
 		 VIDIOC_QBUF 1)              bttv_release
 		 VIDIOCMCAPTURE 1)
 
+   OVERLAY	 VIDIOCCAPTURE on            VIDIOCCAPTURE off
+		 VIDIOC_OVERLAY on           VIDIOC_OVERLAY off
+		 3)                          bttv_release
+
    VBI		 VIDIOC_STREAMON             VIDIOC_STREAMOFF
 		 VIDIOC_QBUF 1)              bttv_release
-		 bttv_read, bttv_poll 1) 3)
+		 bttv_read, bttv_poll 1) 4)
 
    1) The resource must be allocated when we enter buffer prepare functions
       and remain allocated while buffers are in the DMA queue.
    2) This is a single frame read.
-   3) This is a continuous read, implies VIDIOC_STREAMON.
+   3) VIDIOC_S_FBUF and VIDIOC_S_FMT (OVERLAY) still work when
+      RESOURCE_OVERLAY is allocated.
+   4) This is a continuous read, implies VIDIOC_STREAMON.
 
    Note this driver permits video input and standard changes regardless if
    resources are allocated.
@@ -639,7 +646,8 @@  static const unsigned int FORMATS = ARRA
 
 #define VBI_RESOURCES (RESOURCE_VBI)
 #define VIDEO_RESOURCES (RESOURCE_VIDEO_READ | \
-			 RESOURCE_VIDEO_STREAM)
+			 RESOURCE_VIDEO_STREAM | \
+			 RESOURCE_OVERLAY)
 
 static
 int check_alloc_btres_lock(struct bttv *btv, struct bttv_fh *fh, int bit)
@@ -1485,6 +1493,37 @@  format_by_fourcc(int fourcc)
 }
 
 /* ----------------------------------------------------------------------- */
+/* misc helpers                                                            */
+
+static int
+bttv_switch_overlay(struct bttv *btv, struct bttv_fh *fh,
+		    struct bttv_buffer *new)
+{
+	struct bttv_buffer *old;
+	unsigned long flags;
+
+	dprintk("switch_overlay: enter [new=%p]\n", new);
+	if (new)
+		new->vb.state = VIDEOBUF_DONE;
+	spin_lock_irqsave(&btv->s_lock,flags);
+	old = btv->screen;
+	btv->screen = new;
+	btv->loop_irq |= 1;
+	bttv_set_dma(btv, 0x03);
+	spin_unlock_irqrestore(&btv->s_lock,flags);
+	if (NULL != old) {
+		dprintk("switch_overlay: old=%p state is %d\n",
+			old, old->vb.state);
+		bttv_dma_free(&fh->cap,btv, old);
+		kfree(old);
+	}
+	if (NULL == new)
+		free_btres_lock(btv,fh,RESOURCE_OVERLAY);
+	dprintk("switch_overlay: done\n");
+	return 0;
+}
+
+/* ----------------------------------------------------------------------- */
 /* video4linux (1) interface                                               */
 
 static int bttv_prepare_buffer(struct videobuf_queue *q,struct bttv *btv,
@@ -2007,6 +2046,150 @@  limit_scaled_size_lock       (struct btt
 	return rc;
 }
 
+/* Returns an error if the given overlay window dimensions are not
+   possible with the current cropping parameters. If adjust_size is
+   TRUE the function may adjust the window width and/or height
+   instead, however it always rounds the horizontal position and
+   width as btcx_align() does. If adjust_crop is TRUE the function
+   may also adjust the current cropping parameters to get closer
+   to the desired window size. */
+static int
+verify_window_lock(struct bttv_fh *fh, struct v4l2_window *win,
+			 int adjust_size, int adjust_crop)
+{
+	enum v4l2_field field;
+	unsigned int width_mask;
+
+	if (win->w.width < 48)
+		win->w.width = 48;
+	if (win->w.height < 32)
+		win->w.height = 32;
+	if (win->clipcount > 2048)
+		win->clipcount = 2048;
+
+	win->chromakey = 0;
+	win->global_alpha = 0;
+	field = win->field;
+
+	switch (field) {
+	case V4L2_FIELD_TOP:
+	case V4L2_FIELD_BOTTOM:
+	case V4L2_FIELD_INTERLACED:
+		break;
+	default:
+		field = V4L2_FIELD_ANY;
+		break;
+	}
+	if (V4L2_FIELD_ANY == field) {
+		__s32 height2;
+
+		height2 = fh->btv->crop[!!fh->do_crop].rect.height >> 1;
+		field = (win->w.height > height2)
+			? V4L2_FIELD_INTERLACED
+			: V4L2_FIELD_TOP;
+	}
+	win->field = field;
+
+	if (NULL == fh->ovfmt)
+		return -EINVAL;
+	/* 4-byte alignment. */
+	width_mask = ~0;
+	switch (fh->ovfmt->depth) {
+	case 8:
+	case 24:
+		width_mask = ~3;
+		break;
+	case 16:
+		width_mask = ~1;
+		break;
+	case 32:
+		break;
+	default:
+		BUG();
+	}
+
+	win->w.width -= win->w.left & ~width_mask;
+	win->w.left = (win->w.left - width_mask - 1) & width_mask;
+
+	return limit_scaled_size_lock(fh, &win->w.width, &win->w.height,
+				      field, width_mask,
+				      /* width_bias: round down */ 0,
+				      adjust_size, adjust_crop);
+}
+
+static int setup_window_lock(struct bttv_fh *fh, struct bttv *btv,
+			struct v4l2_window *win, int fixup)
+{
+	struct v4l2_clip *clips = NULL;
+	int n,size,retval = 0;
+
+	if (NULL == fh->ovfmt)
+		return -EINVAL;
+	if (!(fh->ovfmt->flags & FORMAT_FLAGS_PACKED))
+		return -EINVAL;
+	retval = verify_window_lock(fh, win,
+			       /* adjust_size */ fixup,
+			       /* adjust_crop */ fixup);
+	if (0 != retval)
+		return retval;
+
+	/* copy clips  --  luckily v4l1 + v4l2 are binary
+	   compatible here ...*/
+	n = win->clipcount;
+	size = sizeof(*clips)*(n+4);
+	clips = kmalloc(size,GFP_KERNEL);
+	if (NULL == clips)
+		return -ENOMEM;
+	if (n > 0)
+		memcpy(clips, win->clips, sizeof(struct v4l2_clip) * n);
+
+	/* clip against screen */
+	if (NULL != btv->fbuf.base)
+		n = btcx_screen_clips(btv->fbuf.fmt.width, btv->fbuf.fmt.height,
+				      &win->w, clips, n);
+	btcx_sort_clips(clips,n);
+
+	/* 4-byte alignments */
+	switch (fh->ovfmt->depth) {
+	case 8:
+	case 24:
+		btcx_align(&win->w, clips, n, 3);
+		break;
+	case 16:
+		btcx_align(&win->w, clips, n, 1);
+		break;
+	case 32:
+		/* no alignment fixups needed */
+		break;
+	default:
+		BUG();
+	}
+
+	kfree(fh->ov.clips);
+	fh->ov.clips    = clips;
+	fh->ov.nclips   = n;
+
+	fh->ov.w        = win->w;
+	fh->ov.field    = win->field;
+	fh->ov.setup_ok = 1;
+
+	btv->init.ov.w.width   = win->w.width;
+	btv->init.ov.w.height  = win->w.height;
+	btv->init.ov.field     = win->field;
+
+	/* update overlay if needed */
+	retval = 0;
+	if (check_btres(fh, RESOURCE_OVERLAY)) {
+		struct bttv_buffer *new;
+
+		new = videobuf_sg_alloc(sizeof(*new));
+		new->crop = btv->crop[!!fh->do_crop].rect;
+		bttv_overlay_risc(btv, &fh->ov, fh->ovfmt, new);
+		retval = bttv_switch_overlay(btv,fh,new);
+	}
+	return retval;
+}
+
 /* ----------------------------------------------------------------------- */
 
 static struct videobuf_queue* bttv_queue(struct bttv_fh *fh)
@@ -2088,6 +2271,17 @@  static int bttv_g_fmt_vid_cap(struct fil
 	return 0;
 }
 
+static int bttv_g_fmt_vid_overlay(struct file *file, void *priv,
+					struct v4l2_format *f)
+{
+	struct bttv_fh *fh  = priv;
+
+	f->fmt.win.w     = fh->ov.w;
+	f->fmt.win.field = fh->ov.field;
+
+	return 0;
+}
+
 static void bttv_get_width_mask_vid_cap(const struct bttv_format *fmt,
 					unsigned int *width_mask,
 					unsigned int *width_bias)
@@ -2159,6 +2353,17 @@  static int bttv_try_fmt_vid_cap(struct f
 	return 0;
 }
 
+static int bttv_try_fmt_vid_overlay(struct file *file, void *priv,
+						struct v4l2_format *f)
+{
+	struct bttv_fh *fh = priv;
+
+	verify_window_lock(fh, &f->fmt.win,
+			/* adjust_size */ 1,
+			/* adjust_crop */ 0);
+	return 0;
+}
+
 static int bttv_s_fmt_vid_cap(struct file *file, void *priv,
 				struct v4l2_format *f)
 {
@@ -2206,6 +2411,20 @@  static int bttv_s_fmt_vid_cap(struct fil
 	return 0;
 }
 
+static int bttv_s_fmt_vid_overlay(struct file *file, void *priv,
+				struct v4l2_format *f)
+{
+	struct bttv_fh *fh = priv;
+	struct bttv *btv = fh->btv;
+
+	if (no_overlay > 0) {
+		pr_err("V4L2_BUF_TYPE_VIDEO_OVERLAY: no_overlay\n");
+		return -EINVAL;
+	}
+
+	return setup_window_lock(fh, btv, &f->fmt.win, 1);
+}
+
 static int bttv_querycap(struct file *file, void  *priv,
 				struct v4l2_capability *cap)
 {
@@ -2219,6 +2438,8 @@  static int bttv_querycap(struct file *fi
 	strscpy(cap->card, btv->video_dev.name, sizeof(cap->card));
 	cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
 			    V4L2_CAP_STREAMING | V4L2_CAP_DEVICE_CAPS;
+	if (no_overlay <= 0)
+		cap->capabilities |= V4L2_CAP_VIDEO_OVERLAY;
 	if (video_is_registered(&btv->vbi_dev))
 		cap->capabilities |= V4L2_CAP_VBI_CAPTURE;
 	if (video_is_registered(&btv->radio_dev)) {
@@ -2238,8 +2459,7 @@  static int bttv_querycap(struct file *fi
 	return 0;
 }
 
-static int bttv_enum_fmt_vid_cap(struct file *file, void  *priv,
-				 struct v4l2_fmtdesc *f)
+static int bttv_enum_fmt_cap_ovr(struct v4l2_fmtdesc *f)
 {
 	int index = -1, i;
 
@@ -2254,9 +2474,162 @@  static int bttv_enum_fmt_vid_cap(struct
 
 	f->pixelformat = formats[i].fourcc;
 
+	return i;
+}
+
+static int bttv_enum_fmt_vid_cap(struct file *file, void  *priv,
+				struct v4l2_fmtdesc *f)
+{
+	int rc = bttv_enum_fmt_cap_ovr(f);
+
+	if (rc < 0)
+		return rc;
+
+	return 0;
+}
+
+static int bttv_enum_fmt_vid_overlay(struct file *file, void  *priv,
+					struct v4l2_fmtdesc *f)
+{
+	int rc;
+
+	if (no_overlay > 0) {
+		pr_err("V4L2_BUF_TYPE_VIDEO_OVERLAY: no_overlay\n");
+		return -EINVAL;
+	}
+
+	rc = bttv_enum_fmt_cap_ovr(f);
+
+	if (rc < 0)
+		return rc;
+
+	if (!(formats[rc].flags & FORMAT_FLAGS_PACKED))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int bttv_g_fbuf(struct file *file, void *f,
+				struct v4l2_framebuffer *fb)
+{
+	struct bttv_fh *fh = f;
+	struct bttv *btv = fh->btv;
+
+	*fb = btv->fbuf;
+	fb->capability = V4L2_FBUF_CAP_LIST_CLIPPING;
+	fb->flags = V4L2_FBUF_FLAG_PRIMARY;
+	if (fh->ovfmt)
+		fb->fmt.pixelformat  = fh->ovfmt->fourcc;
 	return 0;
 }
 
+static int bttv_overlay(struct file *file, void *f, unsigned int on)
+{
+	struct bttv_fh *fh = f;
+	struct bttv *btv = fh->btv;
+	struct bttv_buffer *new;
+	int retval = 0;
+
+	if (on) {
+		/* verify args */
+		if (unlikely(!btv->fbuf.base)) {
+			return -EINVAL;
+		}
+		if (unlikely(!fh->ov.setup_ok)) {
+			dprintk("%d: overlay: !setup_ok\n", btv->c.nr);
+			retval = -EINVAL;
+		}
+		if (retval)
+			return retval;
+	}
+
+	if (!check_alloc_btres_lock(btv, fh, RESOURCE_OVERLAY))
+		return -EBUSY;
+
+	if (on) {
+		fh->ov.tvnorm = btv->tvnorm;
+		new = videobuf_sg_alloc(sizeof(*new));
+		new->crop = btv->crop[!!fh->do_crop].rect;
+		bttv_overlay_risc(btv, &fh->ov, fh->ovfmt, new);
+	} else {
+		new = NULL;
+	}
+
+	/* switch over */
+	retval = bttv_switch_overlay(btv, fh, new);
+	return retval;
+}
+
+static int bttv_s_fbuf(struct file *file, void *f,
+				const struct v4l2_framebuffer *fb)
+{
+	struct bttv_fh *fh = f;
+	struct bttv *btv = fh->btv;
+	const struct bttv_format *fmt;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN) &&
+		!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	/* check args */
+	fmt = format_by_fourcc(fb->fmt.pixelformat);
+	if (NULL == fmt)
+		return -EINVAL;
+	if (0 == (fmt->flags & FORMAT_FLAGS_PACKED))
+		return -EINVAL;
+
+	retval = -EINVAL;
+	if (fb->flags & V4L2_FBUF_FLAG_OVERLAY) {
+		__s32 width = fb->fmt.width;
+		__s32 height = fb->fmt.height;
+
+		retval = limit_scaled_size_lock(fh, &width, &height,
+					   V4L2_FIELD_INTERLACED,
+					   /* width_mask */ ~3,
+					   /* width_bias */ 2,
+					   /* adjust_size */ 0,
+					   /* adjust_crop */ 0);
+		if (0 != retval)
+			return retval;
+	}
+
+	/* ok, accept it */
+	btv->fbuf.base       = fb->base;
+	btv->fbuf.fmt.width  = fb->fmt.width;
+	btv->fbuf.fmt.height = fb->fmt.height;
+	if (0 != fb->fmt.bytesperline)
+		btv->fbuf.fmt.bytesperline = fb->fmt.bytesperline;
+	else
+		btv->fbuf.fmt.bytesperline = btv->fbuf.fmt.width*fmt->depth/8;
+
+	retval = 0;
+	fh->ovfmt = fmt;
+	btv->init.ovfmt = fmt;
+	if (fb->flags & V4L2_FBUF_FLAG_OVERLAY) {
+		fh->ov.w.left   = 0;
+		fh->ov.w.top    = 0;
+		fh->ov.w.width  = fb->fmt.width;
+		fh->ov.w.height = fb->fmt.height;
+		btv->init.ov.w.width  = fb->fmt.width;
+		btv->init.ov.w.height = fb->fmt.height;
+
+		kfree(fh->ov.clips);
+		fh->ov.clips = NULL;
+		fh->ov.nclips = 0;
+
+		if (check_btres(fh, RESOURCE_OVERLAY)) {
+			struct bttv_buffer *new;
+
+			new = videobuf_sg_alloc(sizeof(*new));
+			new->crop = btv->crop[!!fh->do_crop].rect;
+			bttv_overlay_risc(btv, &fh->ov, fh->ovfmt, new);
+			retval = bttv_switch_overlay(btv, fh, new);
+		}
+	}
+	return retval;
+}
+
 static int bttv_reqbufs(struct file *file, void *priv,
 				struct v4l2_requestbuffers *p)
 {
@@ -2376,7 +2749,8 @@  static int bttv_g_selection(struct file
 	struct bttv_fh *fh = f;
 	struct bttv *btv = fh->btv;
 
-	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
+	    sel->type != V4L2_BUF_TYPE_VIDEO_OVERLAY)
 		return -EINVAL;
 
 	switch (sel->target) {
@@ -2413,7 +2787,8 @@  static int bttv_s_selection(struct file
 	__s32 b_right;
 	__s32 b_bottom;
 
-	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
+	    sel->type != V4L2_BUF_TYPE_VIDEO_OVERLAY)
 		return -EINVAL;
 
 	if (sel->target != V4L2_SEL_TGT_CROP)
@@ -2603,6 +2978,7 @@  static int bttv_open(struct file *file)
 	v4l2_fh_init(&fh->fh, vdev);
 
 	fh->type = type;
+	fh->ov.setup_ok = 0;
 
 	videobuf_queue_sg_init(&fh->cap, &bttv_video_qops,
 			    &btv->c.pci->dev, &btv->s_lock,
@@ -2646,6 +3022,10 @@  static int bttv_release(struct file *fil
 	struct bttv_fh *fh = file->private_data;
 	struct bttv *btv = fh->btv;
 
+	/* turn off overlay */
+	if (check_btres(fh, RESOURCE_OVERLAY))
+		bttv_switch_overlay(btv,fh,NULL);
+
 	/* stop video capture */
 	if (check_btres(fh, RESOURCE_VIDEO_STREAM)) {
 		videobuf_streamoff(&fh->cap);
@@ -2711,6 +3091,10 @@  static const struct v4l2_ioctl_ops bttv_
 	.vidioc_g_fmt_vid_cap           = bttv_g_fmt_vid_cap,
 	.vidioc_try_fmt_vid_cap         = bttv_try_fmt_vid_cap,
 	.vidioc_s_fmt_vid_cap           = bttv_s_fmt_vid_cap,
+	.vidioc_enum_fmt_vid_overlay    = bttv_enum_fmt_vid_overlay,
+	.vidioc_g_fmt_vid_overlay       = bttv_g_fmt_vid_overlay,
+	.vidioc_try_fmt_vid_overlay     = bttv_try_fmt_vid_overlay,
+	.vidioc_s_fmt_vid_overlay       = bttv_s_fmt_vid_overlay,
 	.vidioc_g_fmt_vbi_cap           = bttv_g_fmt_vbi_cap,
 	.vidioc_try_fmt_vbi_cap         = bttv_try_fmt_vbi_cap,
 	.vidioc_s_fmt_vbi_cap           = bttv_s_fmt_vbi_cap,
@@ -2730,6 +3114,9 @@  static const struct v4l2_ioctl_ops bttv_
 	.vidioc_s_tuner                 = bttv_s_tuner,
 	.vidioc_g_selection             = bttv_g_selection,
 	.vidioc_s_selection             = bttv_s_selection,
+	.vidioc_g_fbuf                  = bttv_g_fbuf,
+	.vidioc_s_fbuf                  = bttv_s_fbuf,
+	.vidioc_overlay                 = bttv_overlay,
 	.vidioc_g_parm                  = bttv_g_parm,
 	.vidioc_g_frequency             = bttv_g_frequency,
 	.vidioc_s_frequency             = bttv_s_frequency,
@@ -2999,6 +3386,9 @@  static void bttv_print_riscaddr(struct b
 		? (unsigned long long)btv->curr.top->top.dma : 0,
 		btv->curr.bottom
 		? (unsigned long long)btv->curr.bottom->bottom.dma : 0);
+	pr_info("  scr : o=%08llx e=%08llx\n",
+		btv->screen ? (unsigned long long)btv->screen->top.dma : 0,
+		btv->screen ? (unsigned long long)btv->screen->bottom.dma : 0);
 	bttv_risc_disasm(btv, &btv->main);
 }
 
@@ -3119,9 +3509,28 @@  bttv_irq_next_video(struct bttv *btv, st
 		}
 	}
 
-	dprintk("%d: next set: top=%p bottom=%p [irq=%d,%d]\n",
+	/* screen overlay ? */
+	if (NULL != btv->screen) {
+		if (V4L2_FIELD_HAS_BOTH(btv->screen->vb.field)) {
+			if (NULL == set->top && NULL == set->bottom) {
+				set->top    = btv->screen;
+				set->bottom = btv->screen;
+			}
+		} else {
+			if (V4L2_FIELD_TOP == btv->screen->vb.field &&
+			    NULL == set->top) {
+				set->top = btv->screen;
+			}
+			if (V4L2_FIELD_BOTTOM == btv->screen->vb.field &&
+			    NULL == set->bottom) {
+				set->bottom = btv->screen;
+			}
+		}
+	}
+
+	dprintk("%d: next set: top=%p bottom=%p [screen=%p,irq=%d,%d]\n",
 		btv->c.nr, set->top, set->bottom,
-		set->frame_irq, set->top_irq);
+		btv->screen, set->frame_irq, set->top_irq);
 	return 0;
 }
 
@@ -3475,12 +3884,17 @@  static void bttv_unregister_video(struct
 /* register video4linux devices */
 static int bttv_register_video(struct bttv *btv)
 {
+	if (no_overlay > 0)
+		pr_notice("Overlay support disabled\n");
+
 	/* video */
 	vdev_init(btv, &btv->video_dev, &bttv_video_template, "video");
 	btv->video_dev.device_caps = V4L2_CAP_VIDEO_CAPTURE |
 				     V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
 	if (btv->tuner_type != TUNER_ABSENT)
 		btv->video_dev.device_caps |= V4L2_CAP_TUNER;
+	if (no_overlay <= 0)
+		btv->video_dev.device_caps |= V4L2_CAP_VIDEO_OVERLAY;
 
 	if (video_register_device(&btv->video_dev, VFL_TYPE_VIDEO,
 				  video_nr[btv->c.nr]) < 0)
@@ -3671,9 +4085,14 @@  static int bttv_probe(struct pci_dev *de
 
 	/* fill struct bttv with some useful defaults */
 	btv->init.btv         = btv;
+	btv->init.ov.w.width  = 320;
+	btv->init.ov.w.height = 240;
 	btv->init.fmt         = format_by_fourcc(V4L2_PIX_FMT_BGR24);
 	btv->init.width       = 320;
 	btv->init.height      = 240;
+	btv->init.ov.w.width  = 320;
+	btv->init.ov.w.height = 240;
+	btv->init.ov.field    = V4L2_FIELD_INTERLACED;
 	btv->input = 0;
 
 	v4l2_ctrl_new_std(hdl, &bttv_ctrl_ops,
diff -rupN a/drivers/media/pci/bt8xx/bttv-risc.c b/drivers/media/pci/bt8xx/bttv-risc.c
--- a/drivers/media/pci/bt8xx/bttv-risc.c	2023-04-27 04:46:15.574522003 +0200
+++ b/drivers/media/pci/bt8xx/bttv-risc.c	2023-04-27 04:43:56.240488522 +0200
@@ -231,6 +231,95 @@  bttv_risc_planar(struct bttv *btv, struc
 	return 0;
 }
 
+static int
+bttv_risc_overlay(struct bttv *btv, struct btcx_riscmem *risc,
+		  const struct bttv_format *fmt, struct bttv_overlay *ov,
+		  int skip_even, int skip_odd)
+{
+	int dwords, rc, line, maxy, start, end;
+	unsigned skip, nskips;
+	struct btcx_skiplist *skips;
+	__le32 *rp;
+	u32 ri,ra;
+	u32 addr;
+
+	/* skip list for window clipping */
+	skips = kmalloc_array(ov->nclips, sizeof(*skips),GFP_KERNEL);
+	if (NULL == skips)
+		return -ENOMEM;
+
+	/* estimate risc mem: worst case is (1.5*clip+1) * lines instructions
+	   + sync + jump (all 2 dwords) */
+	dwords  = (3 * ov->nclips + 2) *
+		((skip_even || skip_odd) ? (ov->w.height+1)>>1 :  ov->w.height);
+	dwords += 4;
+	if ((rc = btcx_riscmem_alloc(btv->c.pci,risc,dwords*4)) < 0) {
+		kfree(skips);
+		return rc;
+	}
+
+	/* sync instruction */
+	rp = risc->cpu;
+	*(rp++) = cpu_to_le32(BT848_RISC_SYNC|BT848_FIFO_STATUS_FM1);
+	*(rp++) = cpu_to_le32(0);
+
+	addr  = (unsigned long)btv->fbuf.base;
+	addr += btv->fbuf.fmt.bytesperline * ov->w.top;
+	addr += (fmt->depth >> 3)          * ov->w.left;
+
+	/* scan lines */
+	for (maxy = -1, line = 0; line < ov->w.height;
+	     line++, addr += btv->fbuf.fmt.bytesperline) {
+		if ((btv->opt_vcr_hack) &&
+		     (line >= (ov->w.height - VCR_HACK_LINES)))
+			continue;
+		if ((line%2) == 0  &&  skip_even)
+			continue;
+		if ((line%2) == 1  &&  skip_odd)
+			continue;
+
+		/* calculate clipping */
+		if (line > maxy)
+			btcx_calc_skips(line, ov->w.width, &maxy,
+					skips, &nskips, ov->clips, ov->nclips);
+
+		/* write out risc code */
+		for (start = 0, skip = 0; start < ov->w.width; start = end) {
+			if (skip >= nskips) {
+				ri  = BT848_RISC_WRITE;
+				end = ov->w.width;
+			} else if (start < skips[skip].start) {
+				ri  = BT848_RISC_WRITE;
+				end = skips[skip].start;
+			} else {
+				ri  = BT848_RISC_SKIP;
+				end = skips[skip].end;
+				skip++;
+			}
+			if (BT848_RISC_WRITE == ri)
+				ra = addr + (fmt->depth>>3)*start;
+			else
+				ra = 0;
+
+			if (0 == start)
+				ri |= BT848_RISC_SOL;
+			if (ov->w.width == end)
+				ri |= BT848_RISC_EOL;
+			ri |= (fmt->depth>>3) * (end-start);
+
+			*(rp++)=cpu_to_le32(ri);
+			if (0 != ra)
+				*(rp++)=cpu_to_le32(ra);
+		}
+	}
+
+	/* save pointer to jmp instruction address */
+	risc->jmp = rp;
+	BUG_ON((risc->jmp - risc->cpu + 2) * sizeof(*risc->cpu) > risc->size);
+	kfree(skips);
+	return 0;
+}
+
 /* ---------------------------------------------------------- */
 
 static void
@@ -759,3 +848,45 @@  bttv_buffer_risc(struct bttv *btv, struc
 	buf->btswap   = buf->fmt->btswap;
 	return 0;
 }
+
+/* ---------------------------------------------------------- */
+
+/* calculate geometry, build risc code */
+int
+bttv_overlay_risc(struct bttv *btv,
+		  struct bttv_overlay *ov,
+		  const struct bttv_format *fmt,
+		  struct bttv_buffer *buf)
+{
+	/* check interleave, bottom+top fields */
+	dprintk("%d: overlay fields: %s format: 0x%08x  size: %dx%d\n",
+		btv->c.nr, v4l2_field_names[buf->vb.field],
+		fmt->fourcc, ov->w.width, ov->w.height);
+
+	/* calculate geometry */
+	bttv_calc_geo(btv,&buf->geo,ov->w.width,ov->w.height,
+		      V4L2_FIELD_HAS_BOTH(ov->field),
+		      &bttv_tvnorms[ov->tvnorm],&buf->crop);
+
+	/* build risc code */
+	switch (ov->field) {
+	case V4L2_FIELD_TOP:
+		bttv_risc_overlay(btv, &buf->top,    fmt, ov, 0, 0);
+		break;
+	case V4L2_FIELD_BOTTOM:
+		bttv_risc_overlay(btv, &buf->bottom, fmt, ov, 0, 0);
+		break;
+	case V4L2_FIELD_INTERLACED:
+		bttv_risc_overlay(btv, &buf->top,    fmt, ov, 0, 1);
+		bttv_risc_overlay(btv, &buf->bottom, fmt, ov, 1, 0);
+		break;
+	default:
+		BUG();
+	}
+
+	/* copy format info */
+	buf->btformat = fmt->btformat;
+	buf->btswap   = fmt->btswap;
+	buf->vb.field = ov->field;
+	return 0;
+}
diff -rupN a/drivers/media/pci/bt8xx/bttvp.h b/drivers/media/pci/bt8xx/bttvp.h
--- a/drivers/media/pci/bt8xx/bttvp.h	2023-04-27 04:46:15.574522003 +0200
+++ b/drivers/media/pci/bt8xx/bttvp.h	2023-04-27 04:43:39.128730924 +0200
@@ -50,6 +50,7 @@ 
 #define RISC_SLOT_E_FIELD     12
 #define RISC_SLOT_LOOP        14
 
+#define RESOURCE_OVERLAY       1
 #define RESOURCE_VIDEO_STREAM  2
 #define RESOURCE_VBI           4
 #define RESOURCE_VIDEO_READ    8
@@ -164,6 +165,15 @@  struct bttv_buffer_set {
 	unsigned int           frame_irq;
 };
 
+struct bttv_overlay {
+	unsigned int           tvnorm;
+	struct v4l2_rect       w;
+	enum v4l2_field        field;
+	struct v4l2_clip       *clips;
+	int                    nclips;
+	int                    setup_ok;
+};
+
 struct bttv_vbi_fmt {
 	struct v4l2_vbi_format fmt;
 
@@ -206,6 +216,10 @@  struct bttv_fh {
 	int                      width;
 	int                      height;
 
+	/* video overlay */
+	const struct bttv_format *ovfmt;
+	struct bttv_overlay      ov;
+
 	/* Application called VIDIOC_S_SELECTION. */
 	int                      do_crop;
 
@@ -242,6 +256,12 @@  int bttv_buffer_activate_vbi(struct bttv
 void bttv_dma_free(struct videobuf_queue *q, struct bttv *btv,
 		   struct bttv_buffer *buf);
 
+/* overlay handling */
+int bttv_overlay_risc(struct bttv *btv, struct bttv_overlay *ov,
+		      const struct bttv_format *fmt,
+		      struct bttv_buffer *buf);
+
+
 /* ---------------------------------------------------------- */
 /* bttv-vbi.c                                                 */
 
@@ -259,6 +279,11 @@  int bttv_sub_add_device(struct bttv_core
 int bttv_sub_del_devices(struct bttv_core *core);
 
 /* ---------------------------------------------------------- */
+/* bttv-cards.c                                               */
+
+extern int no_overlay;
+
+/* ---------------------------------------------------------- */
 /* bttv-input.c                                               */
 
 extern void init_bttv_i2c_ir(struct bttv *btv);
@@ -429,6 +454,7 @@  struct bttv {
 	   - must acquire s_lock before changing these
 	   - only the irq handler is supported to touch top + bottom + vcurr */
 	struct btcx_riscmem     main;
+	struct bttv_buffer      *screen;    /* overlay             */
 	struct list_head        capture;    /* video capture queue */
 	struct list_head        vcapture;   /* vbi capture queue   */
 	struct bttv_buffer_set  curr;       /* active buffers      */
@@ -453,7 +479,7 @@  struct bttv {
 	/* used to make dvb-bt8xx autoloadable */
 	struct work_struct request_module_wk;
 
-	/* Default (0) and current (1) video capturing
+	/* Default (0) and current (1) video capturing and overlay
 	   cropping parameters in bttv_tvnorm.cropcap units. Protected
 	   by bttv.lock. */
 	struct bttv_crop crop[2];