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[23/24] drm/bridge: require the .owner to be filled in on drm_bridge_attach

Message ID 20180426223139.16740-24-peda@axentia.se (mailing list archive)
State Not Applicable
Delegated to: Geert Uytterhoeven
Headers show

Commit Message

Peter Rosin April 26, 2018, 10:31 p.m. UTC
The .owner will be handy to have around.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/gpu/drm/drm_bridge.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Daniel Vetter April 30, 2018, 3:24 p.m. UTC | #1
On Fri, Apr 27, 2018 at 12:31:38AM +0200, Peter Rosin wrote:
> The .owner will be handy to have around.
> 
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
>  drivers/gpu/drm/drm_bridge.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 9f023bd84d56..a038da696802 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -115,6 +115,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>  	if (!encoder || !bridge)
>  		return -EINVAL;
>  
> +	if (WARN_ON(!bridge->owner))
> +		return -EINVAL;

I think conceptually this is checked at the wrong place, and I think also misnamed
a bit. The ->owner is essentially the struct device (and its associated
driver) that provides the drm_bridge. As such it should be filled out
already at drm_bridge_add() time, and I think the check should be in
there. For driver-internal bridges it might make sense to also check this
here, not sure. Or just require all bridges get added.

Wrt the name, I think we should call this pdev or something. ->owner
usually means the module owner. I think in other subsystems ->dev is used,
but in drm we use ->dev for the drm_device pointer, so totally different
thing. pdev = physical device is the best I came up with. Better
suggestions very much welcome.
-Daniel

> +
>  	if (previous && (!previous->dev || previous->encoder != encoder))
>  		return -EINVAL;
>  
> -- 
> 2.11.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Peter Rosin April 30, 2018, 8:32 p.m. UTC | #2
On 2018-04-30 17:24, Daniel Vetter wrote:
> On Fri, Apr 27, 2018 at 12:31:38AM +0200, Peter Rosin wrote:
>> The .owner will be handy to have around.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> ---
>>  drivers/gpu/drm/drm_bridge.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
>> index 9f023bd84d56..a038da696802 100644
>> --- a/drivers/gpu/drm/drm_bridge.c
>> +++ b/drivers/gpu/drm/drm_bridge.c
>> @@ -115,6 +115,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>>  	if (!encoder || !bridge)
>>  		return -EINVAL;
>>  
>> +	if (WARN_ON(!bridge->owner))
>> +		return -EINVAL;
> 
> I think conceptually this is checked at the wrong place, and I think also misnamed
> a bit. The ->owner is essentially the struct device (and its associated
> driver) that provides the drm_bridge. As such it should be filled out
> already at drm_bridge_add() time, and I think the check should be in
> there. For driver-internal bridges it might make sense to also check this
> here, not sure. Or just require all bridges get added.

The reason for the position is that while I originally had the WARN in
drm_bridge_add, I found that quite a few bridges never call drm_bridge_add.
So I moved it. Other options are to start requiring all bridge suppliers to
call drm_bridge_add or to have the WARN in both function. Too me, it would
make sense to require all bridge suppliers to call drm_bridge_add, as that
enables other init stuff later, when needed. But that is a hairy patch to
get right, and is probably best left as a separate series.

> Wrt the name, I think we should call this pdev or something. ->owner
> usually means the module owner. I think in other subsystems ->dev is used,
> but in drm we use ->dev for the drm_device pointer, so totally different
> thing. pdev = physical device is the best I came up with. Better
> suggestions very much welcome.

pdev is about as problematic as owner. To me it reads "platform device".
And dev for a drm_device is also somewhat problematic, and I think that
drm would have been better, but dev for drm_device is probably quite
common. But one way to go is to rename the current dev to drm, so that
dev is freed up for the owner/supplier device. But that is a tedious
patch to write (I don't do the cocci thing).

Other suggestions I can think of: odev for owner device, sdev for supplier
device or just plain supplier.

Cheers,
Peter

> -Daniel
> 
>> +
>>  	if (previous && (!previous->dev || previous->encoder != encoder))
>>  		return -EINVAL;
>>  
>> -- 
>> 2.11.0
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 9f023bd84d56..a038da696802 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -115,6 +115,9 @@  int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 	if (!encoder || !bridge)
 		return -EINVAL;
 
+	if (WARN_ON(!bridge->owner))
+		return -EINVAL;
+
 	if (previous && (!previous->dev || previous->encoder != encoder))
 		return -EINVAL;