From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Make blocking commits execute locklessly (just as nonblocking commits do) by scheduling them onto the workqueues as well. There will be a later flush_work() done by whoever called the commit hook to make sure the blocking behaviour of the ioctl/etc. is preserved. I also wondered about just dropping the locks straight from the driver, but I guess whoever called us might still depend on having the locks so that seems like a terrible idea. Also calling commit_tail() directly when not holding the locks would then allow eg. two ioctls to execute full modesets in parallel, which we don't want as we haven't fully evaluated all modeset codepaths for concurrency issues. Currently we achieve serial excution with a combination of an ordered workqueue (for nonblocking commits) and reliance on the singular connection_mutex (for blocking commits), and a flush_workqueue() to sync between the two. So by always scheduling everything onto the workqueues we don't have to worry about racing between the lockless direct commit_tail() calls, and we don't need some kind of new atomic hook that would do said call for us after dropping the locks. Also less codepaths in general seems like a beneficial thing. Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> Cc: Rob Clark <robdclark@xxxxxxxxx> Cc: Simon Ser <contact@xxxxxxxxxxx> Cc: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx> Cc: Jonas Ådahl <jadahl@xxxxxxxxx> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/display/intel_display.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index cd617046e0ee..18a5f14e7f41 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -7771,15 +7771,10 @@ static int intel_atomic_commit(struct drm_device *dev, INIT_WORK(&state->base.commit_work, intel_atomic_commit_work); i915_sw_fence_commit(&state->commit_ready); - if (nonblock && state->modeset) { + if (state->modeset) queue_work(dev_priv->display.wq.modeset, &state->base.commit_work); - } else if (nonblock) { + else queue_work(dev_priv->display.wq.flip, &state->base.commit_work); - } else { - if (state->modeset) - flush_workqueue(dev_priv->display.wq.modeset); - intel_atomic_commit_tail(state); - } return 0; } -- 2.35.1