diff mbox

[v2,6/8] drm: Introduce drm_bridge_mode_valid()

Message ID c4314b22644ed311d246d5aa97b63b3be04212c6.1494347165.git.joabreu@synopsys.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jose Abreu May 9, 2017, 5 p.m. UTC
Introduce a new helper function which calls mode_valid() callback
for all bridges in an encoder chain.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Carlos Palminha <palminha@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Archit Taneja <architt@codeaurora.org>
---
 drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
 include/drm/drm_bridge.h     |  2 ++
 2 files changed, 35 insertions(+)

Comments

Ville Syrjala May 10, 2017, 1:41 p.m. UTC | #1
On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
> Introduce a new helper function which calls mode_valid() callback
> for all bridges in an encoder chain.
> 
> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> Cc: Carlos Palminha <palminha@synopsys.com>
> Cc: Alexey Brodkin <abrodkin@synopsys.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dave Airlie <airlied@linux.ie>
> Cc: Andrzej Hajda <a.hajda@samsung.com>
> Cc: Archit Taneja <architt@codeaurora.org>
> ---
>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
>  include/drm/drm_bridge.h     |  2 ++
>  2 files changed, 35 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 86a7637..dc8cdfe 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
>  
>  /**
> + * drm_bridge_mode_valid - validate the mode against all bridges in the
> + * 			   encoder chain.
> + * @bridge: bridge control structure
> + * @mode: desired mode to be validated
> + *
> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
> + * chain, starting from the first bridge to the last. If at least one bridge
> + * does not accept the mode the function returns the error code.
> + *
> + * Note: the bridge passed should be the one closest to the encoder.
> + *
> + * RETURNS:
> + * MODE_OK on success, drm_mode_status Enum error code on failure
> + */
> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
> +					   const struct drm_display_mode *mode)
> +{
> +	enum drm_mode_status ret = MODE_OK;
> +
> +	if (!bridge)
> +		return ret;
> +
> +	if (bridge->funcs->mode_valid)
> +		ret = bridge->funcs->mode_valid(bridge, mode);
> +
> +	if (ret != MODE_OK)
> +		return ret;
> +
> +	return drm_bridge_mode_valid(bridge->next, mode);

Looks like it should be pretty trivial to avoid the recursion.

Am I correct in interpreting this that bridges have some kind of
a hand rolled linked list implementation? Reusing the standard
linked lists would allow you to use list_for_each() etc.

> +}
> +EXPORT_SYMBOL(drm_bridge_mode_valid);
> +
> +/**
>   * drm_bridge_disable - disables all bridges in the encoder chain
>   * @bridge: bridge control structure
>   *
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 00c6c36..8358eb3 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -233,6 +233,8 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>  bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
>  			const struct drm_display_mode *mode,
>  			struct drm_display_mode *adjusted_mode);
> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
> +					   const struct drm_display_mode *mode);
>  void drm_bridge_disable(struct drm_bridge *bridge);
>  void drm_bridge_post_disable(struct drm_bridge *bridge);
>  void drm_bridge_mode_set(struct drm_bridge *bridge,
> -- 
> 1.9.1
>
Jose Abreu May 10, 2017, 2:01 p.m. UTC | #2
Hi Ville,


On 10-05-2017 14:41, Ville Syrjälä wrote:
> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
>> Introduce a new helper function which calls mode_valid() callback
>> for all bridges in an encoder chain.
>>
>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
>> Cc: Carlos Palminha <palminha@synopsys.com>
>> Cc: Alexey Brodkin <abrodkin@synopsys.com>
>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>> Cc: Dave Airlie <airlied@linux.ie>
>> Cc: Andrzej Hajda <a.hajda@samsung.com>
>> Cc: Archit Taneja <architt@codeaurora.org>
>> ---
>>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
>>  include/drm/drm_bridge.h     |  2 ++
>>  2 files changed, 35 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
>> index 86a7637..dc8cdfe 100644
>> --- a/drivers/gpu/drm/drm_bridge.c
>> +++ b/drivers/gpu/drm/drm_bridge.c
>> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
>>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
>>  
>>  /**
>> + * drm_bridge_mode_valid - validate the mode against all bridges in the
>> + * 			   encoder chain.
>> + * @bridge: bridge control structure
>> + * @mode: desired mode to be validated
>> + *
>> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
>> + * chain, starting from the first bridge to the last. If at least one bridge
>> + * does not accept the mode the function returns the error code.
>> + *
>> + * Note: the bridge passed should be the one closest to the encoder.
>> + *
>> + * RETURNS:
>> + * MODE_OK on success, drm_mode_status Enum error code on failure
>> + */
>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
>> +					   const struct drm_display_mode *mode)
>> +{
>> +	enum drm_mode_status ret = MODE_OK;
>> +
>> +	if (!bridge)
>> +		return ret;
>> +
>> +	if (bridge->funcs->mode_valid)
>> +		ret = bridge->funcs->mode_valid(bridge, mode);
>> +
>> +	if (ret != MODE_OK)
>> +		return ret;
>> +
>> +	return drm_bridge_mode_valid(bridge->next, mode);
> Looks like it should be pretty trivial to avoid the recursion.
>
> Am I correct in interpreting this that bridges have some kind of
> a hand rolled linked list implementation? Reusing the standard
> linked lists would allow you to use list_for_each() etc.

I reused the drm_bridge_mode_fixup but now I see how its done
like that: so that the fixup is propagated in the correct order.
As for mode_valid we just need to check if ret != MODE_OK then I
think we can use the list_for_each_entry(bridge->list).

Best regards,
Jose Miguel Abreu

>
>> +}
>> +EXPORT_SYMBOL(drm_bridge_mode_valid);
>> +
>> +/**
>>   * drm_bridge_disable - disables all bridges in the encoder chain
>>   * @bridge: bridge control structure
>>   *
>> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
>> index 00c6c36..8358eb3 100644
>> --- a/include/drm/drm_bridge.h
>> +++ b/include/drm/drm_bridge.h
>> @@ -233,6 +233,8 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>>  bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
>>  			const struct drm_display_mode *mode,
>>  			struct drm_display_mode *adjusted_mode);
>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
>> +					   const struct drm_display_mode *mode);
>>  void drm_bridge_disable(struct drm_bridge *bridge);
>>  void drm_bridge_post_disable(struct drm_bridge *bridge);
>>  void drm_bridge_mode_set(struct drm_bridge *bridge,
>> -- 
>> 1.9.1
>>
Jose Abreu May 10, 2017, 2:07 p.m. UTC | #3
Hi Ville,


On 10-05-2017 15:01, Jose Abreu wrote:
> Hi Ville,
>
>
> On 10-05-2017 14:41, Ville Syrjälä wrote:
>> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
>>> Introduce a new helper function which calls mode_valid() callback
>>> for all bridges in an encoder chain.
>>>
>>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
>>> Cc: Carlos Palminha <palminha@synopsys.com>
>>> Cc: Alexey Brodkin <abrodkin@synopsys.com>
>>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>> Cc: Dave Airlie <airlied@linux.ie>
>>> Cc: Andrzej Hajda <a.hajda@samsung.com>
>>> Cc: Archit Taneja <architt@codeaurora.org>
>>> ---
>>>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
>>>  include/drm/drm_bridge.h     |  2 ++
>>>  2 files changed, 35 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
>>> index 86a7637..dc8cdfe 100644
>>> --- a/drivers/gpu/drm/drm_bridge.c
>>> +++ b/drivers/gpu/drm/drm_bridge.c
>>> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
>>>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
>>>  
>>>  /**
>>> + * drm_bridge_mode_valid - validate the mode against all bridges in the
>>> + * 			   encoder chain.
>>> + * @bridge: bridge control structure
>>> + * @mode: desired mode to be validated
>>> + *
>>> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
>>> + * chain, starting from the first bridge to the last. If at least one bridge
>>> + * does not accept the mode the function returns the error code.
>>> + *
>>> + * Note: the bridge passed should be the one closest to the encoder.
>>> + *
>>> + * RETURNS:
>>> + * MODE_OK on success, drm_mode_status Enum error code on failure
>>> + */
>>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
>>> +					   const struct drm_display_mode *mode)
>>> +{
>>> +	enum drm_mode_status ret = MODE_OK;
>>> +
>>> +	if (!bridge)
>>> +		return ret;
>>> +
>>> +	if (bridge->funcs->mode_valid)
>>> +		ret = bridge->funcs->mode_valid(bridge, mode);
>>> +
>>> +	if (ret != MODE_OK)
>>> +		return ret;
>>> +
>>> +	return drm_bridge_mode_valid(bridge->next, mode);
>> Looks like it should be pretty trivial to avoid the recursion.
>>
>> Am I correct in interpreting this that bridges have some kind of
>> a hand rolled linked list implementation? Reusing the standard
>> linked lists would allow you to use list_for_each() etc.
> I reused the drm_bridge_mode_fixup but now I see how its done
> like that: so that the fixup is propagated in the correct order.
> As for mode_valid we just need to check if ret != MODE_OK then I
> think we can use the list_for_each_entry(bridge->list).

Oops, I got this wrong sorry. I meant there is a list but its for
all the system bridges. This is a "custom" linked list yeah.

Best regards,
Jose Miguel Abreu

>
> Best regards,
> Jose Miguel Abreu
>
>>> +}
>>> +EXPORT_SYMBOL(drm_bridge_mode_valid);
>>> +
>>> +/**
>>>   * drm_bridge_disable - disables all bridges in the encoder chain
>>>   * @bridge: bridge control structure
>>>   *
>>> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
>>> index 00c6c36..8358eb3 100644
>>> --- a/include/drm/drm_bridge.h
>>> +++ b/include/drm/drm_bridge.h
>>> @@ -233,6 +233,8 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>>>  bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
>>>  			const struct drm_display_mode *mode,
>>>  			struct drm_display_mode *adjusted_mode);
>>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
>>> +					   const struct drm_display_mode *mode);
>>>  void drm_bridge_disable(struct drm_bridge *bridge);
>>>  void drm_bridge_post_disable(struct drm_bridge *bridge);
>>>  void drm_bridge_mode_set(struct drm_bridge *bridge,
>>> -- 
>>> 1.9.1
>>>
Daniel Vetter May 10, 2017, 3:14 p.m. UTC | #4
On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote:
> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
> > Introduce a new helper function which calls mode_valid() callback
> > for all bridges in an encoder chain.
> > 
> > Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> > Cc: Carlos Palminha <palminha@synopsys.com>
> > Cc: Alexey Brodkin <abrodkin@synopsys.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Dave Airlie <airlied@linux.ie>
> > Cc: Andrzej Hajda <a.hajda@samsung.com>
> > Cc: Archit Taneja <architt@codeaurora.org>
> > ---
> >  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
> >  include/drm/drm_bridge.h     |  2 ++
> >  2 files changed, 35 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > index 86a7637..dc8cdfe 100644
> > --- a/drivers/gpu/drm/drm_bridge.c
> > +++ b/drivers/gpu/drm/drm_bridge.c
> > @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
> >  EXPORT_SYMBOL(drm_bridge_mode_fixup);
> >  
> >  /**
> > + * drm_bridge_mode_valid - validate the mode against all bridges in the
> > + * 			   encoder chain.
> > + * @bridge: bridge control structure
> > + * @mode: desired mode to be validated
> > + *
> > + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
> > + * chain, starting from the first bridge to the last. If at least one bridge
> > + * does not accept the mode the function returns the error code.
> > + *
> > + * Note: the bridge passed should be the one closest to the encoder.
> > + *
> > + * RETURNS:
> > + * MODE_OK on success, drm_mode_status Enum error code on failure
> > + */
> > +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
> > +					   const struct drm_display_mode *mode)
> > +{
> > +	enum drm_mode_status ret = MODE_OK;
> > +
> > +	if (!bridge)
> > +		return ret;
> > +
> > +	if (bridge->funcs->mode_valid)
> > +		ret = bridge->funcs->mode_valid(bridge, mode);
> > +
> > +	if (ret != MODE_OK)
> > +		return ret;
> > +
> > +	return drm_bridge_mode_valid(bridge->next, mode);
> 
> Looks like it should be pretty trivial to avoid the recursion.
> 
> Am I correct in interpreting this that bridges have some kind of
> a hand rolled linked list implementation? Reusing the standard
> linked lists would allow you to use list_for_each() etc.

Yeah it's a hand-rolled list, but current hw also has a bridge nesting
depth of 2, so it really doesn't matter. I guess once we have real long
chains of bridges we can fix this (and just using list_head sounds like a
great idea).
-Daniel
Laurent Pinchart May 12, 2017, 9:38 a.m. UTC | #5
Hi Daniel,

On Wednesday 10 May 2017 17:14:33 Daniel Vetter wrote:
> On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote:
> > On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
> > > Introduce a new helper function which calls mode_valid() callback
> > > for all bridges in an encoder chain.
> > > 
> > > Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> > > Cc: Carlos Palminha <palminha@synopsys.com>
> > > Cc: Alexey Brodkin <abrodkin@synopsys.com>
> > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > Cc: Dave Airlie <airlied@linux.ie>
> > > Cc: Andrzej Hajda <a.hajda@samsung.com>
> > > Cc: Archit Taneja <architt@codeaurora.org>
> > > ---
> > > 
> > >  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
> > >  include/drm/drm_bridge.h     |  2 ++
> > >  2 files changed, 35 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > > index 86a7637..dc8cdfe 100644
> > > --- a/drivers/gpu/drm/drm_bridge.c
> > > +++ b/drivers/gpu/drm/drm_bridge.c
> > > @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge
> > > *bridge,
> > > 
> > >  EXPORT_SYMBOL(drm_bridge_mode_fixup);
> > >  
> > >  /**
> > > 
> > > + * drm_bridge_mode_valid - validate the mode against all bridges in the
> > > + * 			   encoder chain.
> > > + * @bridge: bridge control structure
> > > + * @mode: desired mode to be validated
> > > + *
> > > + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the
> > > encoder
> > > + * chain, starting from the first bridge to the last. If at least one
> > > bridge + * does not accept the mode the function returns the error
> > > code.
> > > + *
> > > + * Note: the bridge passed should be the one closest to the encoder.
> > > + *
> > > + * RETURNS:
> > > + * MODE_OK on success, drm_mode_status Enum error code on failure
> > > + */
> > > +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
> > > +					   const struct drm_display_mode 
*mode)
> > > +{
> > > +	enum drm_mode_status ret = MODE_OK;
> > > +
> > > +	if (!bridge)
> > > +		return ret;
> > > +
> > > +	if (bridge->funcs->mode_valid)
> > > +		ret = bridge->funcs->mode_valid(bridge, mode);
> > > +
> > > +	if (ret != MODE_OK)
> > > +		return ret;
> > > +
> > > +	return drm_bridge_mode_valid(bridge->next, mode);
> > 
> > Looks like it should be pretty trivial to avoid the recursion.
> > 
> > Am I correct in interpreting this that bridges have some kind of
> > a hand rolled linked list implementation? Reusing the standard
> > linked lists would allow you to use list_for_each() etc.
> 
> Yeah it's a hand-rolled list, but current hw also has a bridge nesting
> depth of 2, so it really doesn't matter. I guess once we have real long
> chains of bridges we can fix this (and just using list_head sounds like a
> great idea).

Even if not really needed right now, it's a pretty easy cleanup, if Jose has 
time to handle it in v3 of this series let's not postpone it ;-)
Archit Taneja May 12, 2017, 10:50 a.m. UTC | #6
On 05/12/2017 03:08 PM, Laurent Pinchart wrote:
> Hi Daniel,
>
> On Wednesday 10 May 2017 17:14:33 Daniel Vetter wrote:
>> On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote:
>>> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
>>>> Introduce a new helper function which calls mode_valid() callback
>>>> for all bridges in an encoder chain.
>>>>
>>>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
>>>> Cc: Carlos Palminha <palminha@synopsys.com>
>>>> Cc: Alexey Brodkin <abrodkin@synopsys.com>
>>>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>>> Cc: Dave Airlie <airlied@linux.ie>
>>>> Cc: Andrzej Hajda <a.hajda@samsung.com>
>>>> Cc: Archit Taneja <architt@codeaurora.org>
>>>> ---
>>>>
>>>>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
>>>>  include/drm/drm_bridge.h     |  2 ++
>>>>  2 files changed, 35 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
>>>> index 86a7637..dc8cdfe 100644
>>>> --- a/drivers/gpu/drm/drm_bridge.c
>>>> +++ b/drivers/gpu/drm/drm_bridge.c
>>>> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge
>>>> *bridge,
>>>>
>>>>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
>>>>
>>>>  /**
>>>>
>>>> + * drm_bridge_mode_valid - validate the mode against all bridges in the
>>>> + * 			   encoder chain.
>>>> + * @bridge: bridge control structure
>>>> + * @mode: desired mode to be validated
>>>> + *
>>>> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the
>>>> encoder
>>>> + * chain, starting from the first bridge to the last. If at least one
>>>> bridge + * does not accept the mode the function returns the error
>>>> code.
>>>> + *
>>>> + * Note: the bridge passed should be the one closest to the encoder.
>>>> + *
>>>> + * RETURNS:
>>>> + * MODE_OK on success, drm_mode_status Enum error code on failure
>>>> + */
>>>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
>>>> +					   const struct drm_display_mode
> *mode)
>>>> +{
>>>> +	enum drm_mode_status ret = MODE_OK;
>>>> +
>>>> +	if (!bridge)
>>>> +		return ret;
>>>> +
>>>> +	if (bridge->funcs->mode_valid)
>>>> +		ret = bridge->funcs->mode_valid(bridge, mode);
>>>> +
>>>> +	if (ret != MODE_OK)
>>>> +		return ret;
>>>> +
>>>> +	return drm_bridge_mode_valid(bridge->next, mode);
>>>
>>> Looks like it should be pretty trivial to avoid the recursion.
>>>
>>> Am I correct in interpreting this that bridges have some kind of
>>> a hand rolled linked list implementation? Reusing the standard
>>> linked lists would allow you to use list_for_each() etc.
>>
>> Yeah it's a hand-rolled list, but current hw also has a bridge nesting
>> depth of 2, so it really doesn't matter. I guess once we have real long
>> chains of bridges we can fix this (and just using list_head sounds like a
>> great idea).
>
> Even if not really needed right now, it's a pretty easy cleanup, if Jose has
> time to handle it in v3 of this series let's not postpone it ;-)

jfyi, some of the bridge functions call the ops from the last bridge in the
chain to first, so we'd need to use list_for_each_entry_prev() (or something
like that) for them.

Archit
Laurent Pinchart May 12, 2017, 11:01 a.m. UTC | #7
Hi Archit,

On Friday 12 May 2017 16:20:07 Archit Taneja wrote:
> On 05/12/2017 03:08 PM, Laurent Pinchart wrote:
> > On Wednesday 10 May 2017 17:14:33 Daniel Vetter wrote:
> >> On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote:
> >>> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
> >>>> Introduce a new helper function which calls mode_valid() callback
> >>>> for all bridges in an encoder chain.
> >>>> 
> >>>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> >>>> Cc: Carlos Palminha <palminha@synopsys.com>
> >>>> Cc: Alexey Brodkin <abrodkin@synopsys.com>
> >>>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> >>>> Cc: Dave Airlie <airlied@linux.ie>
> >>>> Cc: Andrzej Hajda <a.hajda@samsung.com>
> >>>> Cc: Archit Taneja <architt@codeaurora.org>
> >>>> ---
> >>>> 
> >>>>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
> >>>>  include/drm/drm_bridge.h     |  2 ++
> >>>>  2 files changed, 35 insertions(+)
> >>>> 
> >>>> diff --git a/drivers/gpu/drm/drm_bridge.c
> >>>> b/drivers/gpu/drm/drm_bridge.c
> >>>> index 86a7637..dc8cdfe 100644
> >>>> --- a/drivers/gpu/drm/drm_bridge.c
> >>>> +++ b/drivers/gpu/drm/drm_bridge.c
> >>>> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge
> >>>> *bridge,
> >>>> 
> >>>>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
> >>>>  
> >>>>  /**
> >>>> 
> >>>> + * drm_bridge_mode_valid - validate the mode against all bridges in
> >>>> the
> >>>> + * 			   encoder chain.
> >>>> + * @bridge: bridge control structure
> >>>> + * @mode: desired mode to be validated
> >>>> + *
> >>>> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the
> >>>> encoder
> >>>> + * chain, starting from the first bridge to the last. If at least one
> >>>> bridge + * does not accept the mode the function returns the error
> >>>> code.
> >>>> + *
> >>>> + * Note: the bridge passed should be the one closest to the encoder.
> >>>> + *
> >>>> + * RETURNS:
> >>>> + * MODE_OK on success, drm_mode_status Enum error code on failure
> >>>> + */
> >>>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
> >>>> +					   const struct 
drm_display_mode
> > 
> > *mode)
> > 
> >>>> +{
> >>>> +	enum drm_mode_status ret = MODE_OK;
> >>>> +
> >>>> +	if (!bridge)
> >>>> +		return ret;
> >>>> +
> >>>> +	if (bridge->funcs->mode_valid)
> >>>> +		ret = bridge->funcs->mode_valid(bridge, mode);
> >>>> +
> >>>> +	if (ret != MODE_OK)
> >>>> +		return ret;
> >>>> +
> >>>> +	return drm_bridge_mode_valid(bridge->next, mode);
> >>> 
> >>> Looks like it should be pretty trivial to avoid the recursion.
> >>> 
> >>> Am I correct in interpreting this that bridges have some kind of
> >>> a hand rolled linked list implementation? Reusing the standard
> >>> linked lists would allow you to use list_for_each() etc.
> >> 
> >> Yeah it's a hand-rolled list, but current hw also has a bridge nesting
> >> depth of 2, so it really doesn't matter. I guess once we have real long
> >> chains of bridges we can fix this (and just using list_head sounds like a
> >> great idea).
> > 
> > Even if not really needed right now, it's a pretty easy cleanup, if Jose
> > has time to handle it in v3 of this series let's not postpone it ;-)
> 
> jfyi, some of the bridge functions call the ops from the last bridge in the
> chain to first, so we'd need to use list_for_each_entry_prev() (or something
> like that) for them.

And now that I think about it, for some of the operations (especially 
enable/disable) I believe that the bridge should be able to decide whether to 
call the next/previous bridge first or to configure its hardware first. I can 
image bridges that need the previous bridge in the chain to provide a valid 
clock before they get started, as well as bridges that need to be started with 
the incoming video signal stopped.
Archit Taneja May 15, 2017, 4:18 a.m. UTC | #8
On 05/12/2017 04:31 PM, Laurent Pinchart wrote:
> Hi Archit,
>
> On Friday 12 May 2017 16:20:07 Archit Taneja wrote:
>> On 05/12/2017 03:08 PM, Laurent Pinchart wrote:
>>> On Wednesday 10 May 2017 17:14:33 Daniel Vetter wrote:
>>>> On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote:
>>>>> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
>>>>>> Introduce a new helper function which calls mode_valid() callback
>>>>>> for all bridges in an encoder chain.
>>>>>>
>>>>>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
>>>>>> Cc: Carlos Palminha <palminha@synopsys.com>
>>>>>> Cc: Alexey Brodkin <abrodkin@synopsys.com>
>>>>>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>>>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>>>>> Cc: Dave Airlie <airlied@linux.ie>
>>>>>> Cc: Andrzej Hajda <a.hajda@samsung.com>
>>>>>> Cc: Archit Taneja <architt@codeaurora.org>
>>>>>> ---
>>>>>>
>>>>>>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
>>>>>>  include/drm/drm_bridge.h     |  2 ++
>>>>>>  2 files changed, 35 insertions(+)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/drm_bridge.c
>>>>>> b/drivers/gpu/drm/drm_bridge.c
>>>>>> index 86a7637..dc8cdfe 100644
>>>>>> --- a/drivers/gpu/drm/drm_bridge.c
>>>>>> +++ b/drivers/gpu/drm/drm_bridge.c
>>>>>> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge
>>>>>> *bridge,
>>>>>>
>>>>>>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
>>>>>>
>>>>>>  /**
>>>>>>
>>>>>> + * drm_bridge_mode_valid - validate the mode against all bridges in
>>>>>> the
>>>>>> + * 			   encoder chain.
>>>>>> + * @bridge: bridge control structure
>>>>>> + * @mode: desired mode to be validated
>>>>>> + *
>>>>>> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the
>>>>>> encoder
>>>>>> + * chain, starting from the first bridge to the last. If at least one
>>>>>> bridge + * does not accept the mode the function returns the error
>>>>>> code.
>>>>>> + *
>>>>>> + * Note: the bridge passed should be the one closest to the encoder.
>>>>>> + *
>>>>>> + * RETURNS:
>>>>>> + * MODE_OK on success, drm_mode_status Enum error code on failure
>>>>>> + */
>>>>>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
>>>>>> +					   const struct
> drm_display_mode
>>>
>>> *mode)
>>>
>>>>>> +{
>>>>>> +	enum drm_mode_status ret = MODE_OK;
>>>>>> +
>>>>>> +	if (!bridge)
>>>>>> +		return ret;
>>>>>> +
>>>>>> +	if (bridge->funcs->mode_valid)
>>>>>> +		ret = bridge->funcs->mode_valid(bridge, mode);
>>>>>> +
>>>>>> +	if (ret != MODE_OK)
>>>>>> +		return ret;
>>>>>> +
>>>>>> +	return drm_bridge_mode_valid(bridge->next, mode);
>>>>>
>>>>> Looks like it should be pretty trivial to avoid the recursion.
>>>>>
>>>>> Am I correct in interpreting this that bridges have some kind of
>>>>> a hand rolled linked list implementation? Reusing the standard
>>>>> linked lists would allow you to use list_for_each() etc.
>>>>
>>>> Yeah it's a hand-rolled list, but current hw also has a bridge nesting
>>>> depth of 2, so it really doesn't matter. I guess once we have real long
>>>> chains of bridges we can fix this (and just using list_head sounds like a
>>>> great idea).
>>>
>>> Even if not really needed right now, it's a pretty easy cleanup, if Jose
>>> has time to handle it in v3 of this series let's not postpone it ;-)
>>
>> jfyi, some of the bridge functions call the ops from the last bridge in the
>> chain to first, so we'd need to use list_for_each_entry_prev() (or something
>> like that) for them.
>
> And now that I think about it, for some of the operations (especially
> enable/disable) I believe that the bridge should be able to decide whether to
> call the next/previous bridge first or to configure its hardware first. I can
> image bridges that need the previous bridge in the chain to provide a valid
> clock before they get started, as well as bridges that need to be started with
> the incoming video signal stopped.

I guess converting into list would be a good start to achieve this. We'd probably
need to extend/redo the drm_bridge_attach() API to tweak the order in the which
the ops are called.

Thanks,
Archit
Daniel Vetter May 15, 2017, 6:49 a.m. UTC | #9
On Fri, May 12, 2017 at 02:01:49PM +0300, Laurent Pinchart wrote:
> Hi Archit,
> 
> On Friday 12 May 2017 16:20:07 Archit Taneja wrote:
> > On 05/12/2017 03:08 PM, Laurent Pinchart wrote:
> > > On Wednesday 10 May 2017 17:14:33 Daniel Vetter wrote:
> > >> On Wed, May 10, 2017 at 04:41:09PM +0300, Ville Syrjälä wrote:
> > >>> On Tue, May 09, 2017 at 06:00:13PM +0100, Jose Abreu wrote:
> > >>>> Introduce a new helper function which calls mode_valid() callback
> > >>>> for all bridges in an encoder chain.
> > >>>> 
> > >>>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> > >>>> Cc: Carlos Palminha <palminha@synopsys.com>
> > >>>> Cc: Alexey Brodkin <abrodkin@synopsys.com>
> > >>>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > >>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > >>>> Cc: Dave Airlie <airlied@linux.ie>
> > >>>> Cc: Andrzej Hajda <a.hajda@samsung.com>
> > >>>> Cc: Archit Taneja <architt@codeaurora.org>
> > >>>> ---
> > >>>> 
> > >>>>  drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
> > >>>>  include/drm/drm_bridge.h     |  2 ++
> > >>>>  2 files changed, 35 insertions(+)
> > >>>> 
> > >>>> diff --git a/drivers/gpu/drm/drm_bridge.c
> > >>>> b/drivers/gpu/drm/drm_bridge.c
> > >>>> index 86a7637..dc8cdfe 100644
> > >>>> --- a/drivers/gpu/drm/drm_bridge.c
> > >>>> +++ b/drivers/gpu/drm/drm_bridge.c
> > >>>> @@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge
> > >>>> *bridge,
> > >>>> 
> > >>>>  EXPORT_SYMBOL(drm_bridge_mode_fixup);
> > >>>>  
> > >>>>  /**
> > >>>> 
> > >>>> + * drm_bridge_mode_valid - validate the mode against all bridges in
> > >>>> the
> > >>>> + * 			   encoder chain.
> > >>>> + * @bridge: bridge control structure
> > >>>> + * @mode: desired mode to be validated
> > >>>> + *
> > >>>> + * Calls &drm_bridge_funcs.mode_valid for all the bridges in the
> > >>>> encoder
> > >>>> + * chain, starting from the first bridge to the last. If at least one
> > >>>> bridge + * does not accept the mode the function returns the error
> > >>>> code.
> > >>>> + *
> > >>>> + * Note: the bridge passed should be the one closest to the encoder.
> > >>>> + *
> > >>>> + * RETURNS:
> > >>>> + * MODE_OK on success, drm_mode_status Enum error code on failure
> > >>>> + */
> > >>>> +enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
> > >>>> +					   const struct 
> drm_display_mode
> > > 
> > > *mode)
> > > 
> > >>>> +{
> > >>>> +	enum drm_mode_status ret = MODE_OK;
> > >>>> +
> > >>>> +	if (!bridge)
> > >>>> +		return ret;
> > >>>> +
> > >>>> +	if (bridge->funcs->mode_valid)
> > >>>> +		ret = bridge->funcs->mode_valid(bridge, mode);
> > >>>> +
> > >>>> +	if (ret != MODE_OK)
> > >>>> +		return ret;
> > >>>> +
> > >>>> +	return drm_bridge_mode_valid(bridge->next, mode);
> > >>> 
> > >>> Looks like it should be pretty trivial to avoid the recursion.
> > >>> 
> > >>> Am I correct in interpreting this that bridges have some kind of
> > >>> a hand rolled linked list implementation? Reusing the standard
> > >>> linked lists would allow you to use list_for_each() etc.
> > >> 
> > >> Yeah it's a hand-rolled list, but current hw also has a bridge nesting
> > >> depth of 2, so it really doesn't matter. I guess once we have real long
> > >> chains of bridges we can fix this (and just using list_head sounds like a
> > >> great idea).
> > > 
> > > Even if not really needed right now, it's a pretty easy cleanup, if Jose
> > > has time to handle it in v3 of this series let's not postpone it ;-)
> > 
> > jfyi, some of the bridge functions call the ops from the last bridge in the
> > chain to first, so we'd need to use list_for_each_entry_prev() (or something
> > like that) for them.
> 
> And now that I think about it, for some of the operations (especially 
> enable/disable) I believe that the bridge should be able to decide whether to 
> call the next/previous bridge first or to configure its hardware first. I can 
> image bridges that need the previous bridge in the chain to provide a valid 
> clock before they get started, as well as bridges that need to be started with 
> the incoming video signal stopped.

That's why we have pre_/post_ hooks ...
-Daniel
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 86a7637..dc8cdfe 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -206,6 +206,39 @@  bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
 EXPORT_SYMBOL(drm_bridge_mode_fixup);
 
 /**
+ * drm_bridge_mode_valid - validate the mode against all bridges in the
+ * 			   encoder chain.
+ * @bridge: bridge control structure
+ * @mode: desired mode to be validated
+ *
+ * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
+ * chain, starting from the first bridge to the last. If at least one bridge
+ * does not accept the mode the function returns the error code.
+ *
+ * Note: the bridge passed should be the one closest to the encoder.
+ *
+ * RETURNS:
+ * MODE_OK on success, drm_mode_status Enum error code on failure
+ */
+enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
+					   const struct drm_display_mode *mode)
+{
+	enum drm_mode_status ret = MODE_OK;
+
+	if (!bridge)
+		return ret;
+
+	if (bridge->funcs->mode_valid)
+		ret = bridge->funcs->mode_valid(bridge, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	return drm_bridge_mode_valid(bridge->next, mode);
+}
+EXPORT_SYMBOL(drm_bridge_mode_valid);
+
+/**
  * drm_bridge_disable - disables all bridges in the encoder chain
  * @bridge: bridge control structure
  *
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 00c6c36..8358eb3 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -233,6 +233,8 @@  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
 			const struct drm_display_mode *mode,
 			struct drm_display_mode *adjusted_mode);
+enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
+					   const struct drm_display_mode *mode);
 void drm_bridge_disable(struct drm_bridge *bridge);
 void drm_bridge_post_disable(struct drm_bridge *bridge);
 void drm_bridge_mode_set(struct drm_bridge *bridge,