From: Robert Foss robert.foss@collabora.com
As per the documentation in drm_crtc.h, atomic_commit should return -EBUSY if an asycnhronous update is requested and there is an earlier update pending.
Note: docs cited here are drm_crtc.h, and the whole quote is:
* - -EBUSY, if an asynchronous updated is requested and there is * an earlier updated pending. Drivers are allowed to support a queue * of outstanding updates, but currently no driver supports that. * Note that drivers must wait for preceding updates to complete if a * synchronous update is requested, they are not allowed to fail the * commit in that case.
Signed-off-by: Robert Foss robert.foss@collabora.com ---
Changes since v1: - Corrected and simplified patch to piggyback on a previously existing check.
drivers/gpu/drm/vc4/vc4_kms.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c index 4718ae5..7c7188d 100644 --- a/drivers/gpu/drm/vc4/vc4_kms.c +++ b/drivers/gpu/drm/vc4/vc4_kms.c @@ -117,10 +117,18 @@ static int vc4_atomic_commit(struct drm_device *dev, return -ENOMEM;
/* Make sure that any outstanding modesets have finished. */ - ret = down_interruptible(&vc4->async_modeset); - if (ret) { - kfree(c); - return ret; + if (async) { + ret = down_trylock(&vc4->async_modeset); + if (ret) { + kfree(c); + return -EBUSY; + } + } else { + ret = down_interruptible(&vc4->async_modeset); + if (ret) { + kfree(c); + return ret; + } }
ret = drm_atomic_helper_prepare_planes(dev, state);