[PATCH 1/2] drm/atomic: Make atomic helper track newly assigned planes correctly.

[Maarten Lankhorst]

Op 16-10-17 om 15:42 schreef Ville Syrjälä:
> On Mon, Oct 16, 2017 at 03:29:27PM +0200, Maarten Lankhorst wrote:
>> Commit 669c9215afea ("drm/atomic: Make async plane update checks work as
>> intended, v2.") forced planes to always be tracked, but forgot to
>> explicitly get the crtc commit from the new crtc when available.
>>
>> This broke plane commit tracking, and caused kms_atomic_transitions
>> to randomly fail with -EBUSY.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>> Fixes: 669c9215afea ("drm/atomic: Make async plane update checks work as intended, v2.")
>> Cc: Gustavo Padovan <gustavo.padovan at collabora.com>
>> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102671
>> Testcase: kms_atomic_transitions
>> ---
>>  drivers/gpu/drm/drm_atomic_helper.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
>> index d59441f1dcd4..b64c8f5bc940 100644
>> --- a/drivers/gpu/drm/drm_atomic_helper.c
>> +++ b/drivers/gpu/drm/drm_atomic_helper.c
>> @@ -1804,7 +1804,7 @@ int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
>>  		    !try_wait_for_completion(&old_plane_state->commit->flip_done))
>>  			return -EBUSY;
>>  
>> -		commit = crtc_or_fake_commit(state, old_plane_state->crtc);
>> +		commit = crtc_or_fake_commit(state, old_plane_state->crtc ?: new_plane_state->crtc);
> Shouldn't old vs. new state be the other way around?
Hmm to be honest, could be. We don't allow crtc's to switch planes directly. So in practice it doesn't matter.
But if we ever did allow moving crtc's, it's up for debate what crtc we want to use here..