Re: [Intel-gfx] [PATCH v2 1/2] drm/atomic: move waiting for hw_done to a helper

On Wed, Jun 14, 2017 at 11:08:41AM +0200, Maarten Lankhorst wrote:

Moving the wait to a helper allows callers outside of the core to wait for pending updates to complete.

This can be used to prevent races against nonblocking modesets. Only the hw_done call in swap_state is moved to a helper, doing it for the other callers requires too many changes and I think this is the only useful one to export.

Signed-off-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com

drivers/gpu/drm/drm_atomic_helper.c | 51 +++++++++++++++++++++++++++---------- include/drm/drm_atomic_helper.h | 1 + 2 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 86d3093c6c9b..1b068ce1aea9 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -2067,6 +2067,41 @@ void drm_atomic_helper_cleanup_planes(struct drm_device *dev, EXPORT_SYMBOL(drm_atomic_helper_cleanup_planes);

/**

• • drm_atomic_helper_wait_for_hw_done - wait for all previous hw updates to complete.
• • @crtc: crtc to wait on.
• • This function waits for all previous hardware updates queued on @crtc
• • to complete.
• • Returns:
• • 0 on success, negative error code on failure.
• */

+int drm_atomic_helper_wait_for_hw_done(struct drm_crtc *crtc) +{

• struct drm_crtc_commit *commit;
• long ret;
• 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)

• return 0;
  

• ret = wait_for_completion_timeout(&commit->hw_done, 10 * HZ);
• drm_crtc_commit_put(commit);
• if (ret == 0)

• return -EBUSY;
  

-ETIMEDOUT ?

• return ret > 0 ? 0 : ret;

+} +EXPORT_SYMBOL(drm_atomic_helper_wait_for_hw_done);

+/**

• drm_atomic_helper_swap_state - store atomic state into current sw state
• @state: atomic state
• @stall: stall for proceeding commits

@@ -2107,28 +2142,16 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state, struct drm_crtc_state *old_crtc_state, *new_crtc_state; struct drm_plane *plane; struct drm_plane_state *old_plane_state, *new_plane_state;

• struct drm_crtc_commit *commit; void *obj, *obj_state; const struct drm_private_state_funcs *funcs;

  if (stall) { for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {

• 	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);
  

• 	ret = drm_atomic_helper_wait_for_hw_done(crtc);
  
  

• 	if (!commit)
  

• 		continue;
  

• 	ret = wait_for_completion_timeout(&commit->hw_done,
  

• 					  10*HZ);
  

• 	if (ret == 0)
  

• 	if (ret < 0)
  	DRM_ERROR("[CRTC:%d:%s] hw_done timed out\n",
  		  crtc->base.id, crtc->name);
  

• 	drm_crtc_commit_put(commit);
  

  } }

diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h index f0a8678ae98e..175a1a3fed36 100644 --- a/include/drm/drm_atomic_helper.h +++ b/include/drm/drm_atomic_helper.h @@ -77,6 +77,7 @@ void drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc_state *old_crtc_state, bool atomic);

+int drm_atomic_helper_wait_for_hw_done(struct drm_crtc *crtc); void drm_atomic_helper_swap_state(struct drm_atomic_state *state, bool stall);

-- 2.11.0

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