[PATCH 1/2] Revert "drm: omapdrm: Let the DRM core skip plane commit on inactive CRTCs"

[Tomi Valkeinen]

On 28/01/17 18:11, Laurent Pinchart wrote:
> Hi Jyri,
> 
> Thank you for the patch.
> 
> On Friday 27 Jan 2017 12:04:54 Jyri Sarha wrote:
>> This reverts commit dadf4659d0608e034b6633f30300c2eff2dafb4c.
>>
>> If planes are not disabled when the they are not on any crtc anymore
>> they will remain active and may show as "ghosts" when the crtc they
>> were last on is active again.
> 
> Sorry for the breakage.
> 
> The drm_atomic_helper_commit_planes() helper documentation states
> 
>  * Unless otherwise needed, drivers are advised to set the ACTIVE_ONLY flag in
>  * @flags in order not to receive plane update notifications related to a
>  * disabled CRTC. This avoids the need to manually ignore plane updates in
>  * driver code when the driver and/or hardware can't or just don't need to
>  * deal with updates on disabled CRTCs, for example when supporting runtime
>  * PM.
> 
> I wonder what this implies when CRTCs are being disabled. I see very few cases 
> where the hardware wouldn't need the plane atomic disable operation being 
> called when a plane is being disabled due to its CRTC being disabled. Maybe 
> this should thus be addressed in the core. Daniel, any comment on this ?

Similar change was done to mali in "drm: mali-dp: Don't set
DRM_PLANE_COMMIT_ACTIVE_ONLY", so at least omapdrm is not alone here. I
also wonder if this behavior is correct.

 Tomi

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