[PATCH v3 1/6] drm: Add drm_mode_config->normalize_zpos boolean

[Peter Ujfalusi]

Ville,

On 2018-01-26 18:43, Ville Syrjälä wrote:
>> I'm not sure if I understand the problem. This series does the following
>> in essence:
>>
>> drm_atomic_helper_check(...)
>> {
>> 	/* does A */
>> }
>>
>> driver_hand_rolled_atomic_helper_check(...)
>> {
>> 	/* does A */
>> }
>>
>> - .atomic_check = driver_hand_rolled_atomic_helper_check,
>> + .atomic_check = drm_atomic_helper_check,
>>
>> I'm most likely missing something, but not sure what.
> 
> The 
> 
> if (state->legacy_cursor_update)
> 	state->async_update = !drm_atomic_helper_async_check(drm, state);
> 
> part.

Yes, you are right. this part is missing from the hand rolled
atomic_check function in the drivers I'm touching in this series.

The reason for that is that they all got their atomic_check function
copied from the core before the legacy_cursor_update check and async
check is added. Drivers just 'left behind' by not getting the same change.

Which might or might not cause issues for them, but it is still better
to use common code as much as possible to have consistent way of working
among the DRM drivers.

> The helper has it, as does tegra, but sti does not. Would be nice to
> have something in the comment message documenting why it's safe to add
> it to sti and other drivers that didn't already have it.

I purposefully created separate patches for the drivers so the change
can be reverted easier.

I can add to the commit message for the drivers something like:

Note: the drm_atomic_helper_check() now includes

if (state->legacy_cursor_update)
	state->async_update = !drm_atomic_helper_async_check(drm, state);

which was added after the driver moved away from using it
(38d868e41c4b9250d5a115c049dc2d48f4909581 drm: Don't force all planes to
be added to the state due to zpos)

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki