[Why]
Atomic check can't truly be non-blocking if amdgpu_dm is waiting for
hw_done and flip_done in atomic check. This introduces waits when
any previous non-blocking commits queued work on a worker thread and
a new atomic commit attempts to do another full update/modeset.
[How]
Drop the waits and move the global lock acqusition into atomic check.
This is fine to do since commit tail waits for these dependencies
before calling amdgpu_dm_atomic_commit_tail.
This is only safe as long as DC never queries anything from within
current_state when doing validation in atomic_check. This is the
case as of writing, but any future uses of dc->current_state from
within atomic_check should be considered incorrect.
Cc: Harry Wentland <harry.wentland@xxxxxxx>
Cc: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 58 ++-----------------
1 file changed, 6 insertions(+), 52 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 3ae438d9849f..fe21bb86b66a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5078,57 +5078,6 @@ void dm_restore_drm_connector_state(struct drm_device *dev,
dm_force_atomic_commit(&aconnector->base);
}
-/*
- * Grabs all modesetting locks to serialize against any blocking commits,
- * Waits for completion of all non blocking commits.
- */
-static int do_aquire_global_lock(struct drm_device *dev,
- struct drm_atomic_state *state)
-{
- struct drm_crtc *crtc;
- struct drm_crtc_commit *commit;
- long ret;
-
- /*
- * Adding all modeset locks to aquire_ctx will
- * ensure that when the framework release it the
- * extra locks we are locking here will get released to
- */
- ret = drm_modeset_lock_all_ctx(dev, state->acquire_ctx);
- if (ret)
- return ret;
-
- list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
- spin_lock(&crtc->commit_lock);
- commit = list_first_entry_or_null(&crtc->commit_list,
- struct drm_crtc_commit, commit_entry);
- if (commit)
- drm_crtc_commit_get(commit);
- spin_unlock(&crtc->commit_lock);
-
- if (!commit)
- continue;
-
- /*
- * Make sure all pending HW programming completed and
- * page flips done
- */
- ret = wait_for_completion_interruptible_timeout(&commit->hw_done, 10*HZ);
-
- if (ret > 0)
- ret = wait_for_completion_interruptible_timeout(
- &commit->flip_done, 10*HZ);
-
- if (ret == 0)
- DRM_ERROR("[CRTC:%d:%s] hw_done or flip_done "
- "timed out\n", crtc->base.id, crtc->name);
-
- drm_crtc_commit_put(commit);
- }
-
- return ret < 0 ? ret : 0;
-}
-
void set_freesync_on_stream(struct amdgpu_display_manager *dm,
struct dm_crtc_state *new_crtc_state,
struct dm_connector_state *new_con_state,
@@ -5793,7 +5742,12 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
if (ret)
goto fail;
- ret = do_aquire_global_lock(dev, state);
+ /*
+ * This should be replaced with finer locking on the
+ * on the appropriate resources when possible.
+ * For now it's safer to grab everything.
+ */
+ ret = drm_modeset_lock_all_ctx(dev, state->acquire_ctx);
if (ret)
goto fail;
--
2.17.1
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