[PATCH] drm/atomic: Make atomic helper track newly assigned planes correctly, v2.

[Daniel Vetter]

On Tue, Oct 17, 2017 at 07:20:47AM +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.
> 
> Changes since v1:
> - Prefer new_crtc_state->crtc above old_crtc_state->crtc.
> 
> 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

Do we need to make this testcase more effective at hitting this?
> ---
>  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..d0c2b266289e 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, new_plane_state->crtc ?: old_plane_state->crtc);

Maybe line-break and don't use the ?: gcc-ism. Either way

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

>  		if (!commit)
>  			return -ENOMEM;
>  
> -- 
> 2.14.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch