[PATCH] drm: rcar-du: Setup planes before enabling CRTC to avoid flicker

[Kieran Bingham]

Hi Maxime,

On 17/07/17 07:32, Maxime Ripard wrote:
> On Thu, Jul 13, 2017 at 05:25:08PM +0100, Kieran Bingham wrote:
>>>>> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
>>>>> index 82b978a5dae6..c2f382feca07 100644
>>>>> --- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
>>>>> +++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
>>>>> @@ -255,9 +255,9 @@ static void rcar_du_atomic_commit_tail(struct drm_atomic_state *old_state)
>>>>>  
>>>>>  	/* Apply the atomic update. */
>>>>>  	drm_atomic_helper_commit_modeset_disables(dev, old_state);
>>>>> -	drm_atomic_helper_commit_modeset_enables(dev, old_state);
>>>>>  	drm_atomic_helper_commit_planes(dev, old_state,
>>>>>  					DRM_PLANE_COMMIT_ACTIVE_ONLY);
>>>>
>>>> Except for DRM_PLANE_COMMIT_ACTIVE_ONLY, this function now looks very much like
>>>> the default drm_atomic_helper_commit_tail() code.
>>>>
>>>> Reading around other uses /variants of commit_tail() style functions in other
>>>> drivers has left me confused as to how the ordering affects things here.
>>>>
>>>> Could be worth adding a comment at least to describe why we can't use the
>>>> default helper...
>>>
>>> Or better still ... Use Maxime's new :
>>>
>>> [PATCH 1/4] drm/atomic: implement drm_atomic_helper_commit_tail for runtime_pm users
>>
>> Never mind - I've just looked again, and seen that this new helper function is
>> the ordering previous to *this* patch, and therefore isn't the same.
>>
>> However - it's worth noting that Maxime's patch converts this function to the
>> new helper - which contradicts this patch's motivations.
> 
> So I guess I should drop the renesas modifications in my serie then?

Yes, Please.

I think we have a few extra modifications in this function as well which will
take it further away from a default implementation.

Regards

Kieran

> 
> Maxime
>