From 42b062b0d9463557966766940791548313df6b55 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 8 Aug 2017 10:08:27 +0200 Subject: [PATCH] drm/i915: Push i915_sw_fence_wait into the nonblocking atomic commit Blocking in a worker is ok, that's what the unbound_wq is for. And it unifies the paths between the blocking and nonblocking commit, giving me just one path where I have to implement the deadlock avoidance trickery in the next patch. I first tried to implement the following patch without this rework, but force-completing i915_sw_fence creates some serious challenges around properly cleaning things up. So wasn't a feasible short-term approach. Another approach would be to simple keep track of all pending atomic commit work items and manually queue them from the reset code. With the caveat that double-queue in case we race with the i915_sw_fence must be avoided. Given all that, taking the cost of a double schedule in atomic for the short-term fix is the best approach, but can be changed in the future of course. v2: Amend commit message (Chris). v3: Add comment explaining why we do nothing in the sw_fence complete callback (Michel). Reviewed-by: Maarten Lankhorst Cc: Chris Wilson Cc: Mika Kuoppala Cc: Joonas Lahtinen Cc: Tvrtko Ursulin (v2) Cc: Michel Thierry Reviewed-by: Michel Thierry Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20170808080828.23650-2-daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/intel_display.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index ee6d3121890e..519aa240cc4c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -12311,6 +12311,8 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state) unsigned crtc_vblank_mask = 0; int i; + i915_sw_fence_wait(&intel_state->commit_ready); + drm_atomic_helper_wait_for_dependencies(state); if (intel_state->modeset) @@ -12476,10 +12478,8 @@ intel_atomic_commit_ready(struct i915_sw_fence *fence, switch (notify) { case FENCE_COMPLETE: - if (state->base.commit_work.func) - queue_work(system_unbound_wq, &state->base.commit_work); + /* we do blocking waits in the worker, nothing to do here */ break; - case FENCE_FREE: { struct intel_atomic_helper *helper = @@ -12581,14 +12581,14 @@ static int intel_atomic_commit(struct drm_device *dev, } drm_atomic_state_get(state); - INIT_WORK(&state->commit_work, - nonblock ? intel_atomic_commit_work : NULL); + INIT_WORK(&state->commit_work, intel_atomic_commit_work); i915_sw_fence_commit(&intel_state->commit_ready); - if (!nonblock) { - i915_sw_fence_wait(&intel_state->commit_ready); + if (nonblock) + queue_work(system_unbound_wq, &state->commit_work); + else intel_atomic_commit_tail(state); - } + return 0; } -- 2.20.1