drm/atomic-helper: remove backoff hack from page_flip

Yay, we can now properly retry in case of deadlocks or whatever!

Also don't forget to remove the transitional crtc->acquire_ctx
assignment again.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322215058.8671-13-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_atomic_helper.c

@@ -2884,34 +2884,16 @@ int drm_atomic_helper_page_flip(struct drm_crtc *crtc,
 	if (!state)
 		return -ENOMEM;
 
-	state->acquire_ctx = drm_modeset_legacy_acquire_ctx(crtc);
+	state->acquire_ctx = ctx;
 
-retry:
 	ret = page_flip_common(state, crtc, fb, event, flags);
 	if (ret != 0)
 		goto fail;
 
 	ret = drm_atomic_nonblocking_commit(state);
-
 fail:
-	if (ret == -EDEADLK)
-		goto backoff;
-
 	drm_atomic_state_put(state);
 	return ret;
-
-backoff:
-	drm_atomic_state_clear(state);
-	drm_atomic_legacy_backoff(state);
-
-	/*
-	 * Someone might have exchanged the framebuffer while we dropped locks
-	 * in the backoff code. We need to fix up the fb refcount tracking the
-	 * core does for us.
-	 */
-	plane->old_fb = plane->fb;
-
-	goto retry;
 }
 EXPORT_SYMBOL(drm_atomic_helper_page_flip);
 
@@ -2948,9 +2930,8 @@ int drm_atomic_helper_page_flip_target(
 	if (!state)
 		return -ENOMEM;
 
-	state->acquire_ctx = drm_modeset_legacy_acquire_ctx(crtc);
+	state->acquire_ctx = ctx;
 
-retry:
 	ret = page_flip_common(state, crtc, fb, event, flags);
 	if (ret != 0)
 		goto fail;
@@ -2963,26 +2944,9 @@ int drm_atomic_helper_page_flip_target(
 	crtc_state->target_vblank = target;
 
 	ret = drm_atomic_nonblocking_commit(state);
-
 fail:
-	if (ret == -EDEADLK)
-		goto backoff;
-
 	drm_atomic_state_put(state);
 	return ret;
-
-backoff:
-	drm_atomic_state_clear(state);
-	drm_atomic_legacy_backoff(state);
-
-	/*
-	 * Someone might have exchanged the framebuffer while we dropped locks
-	 * in the backoff code. We need to fix up the fb refcount tracking the
-	 * core does for us.
-	 */
-	plane->old_fb = plane->fb;
-
-	goto retry;
 }
 EXPORT_SYMBOL(drm_atomic_helper_page_flip_target);
 

drivers/gpu/drm/drm_plane.c

@@ -875,7 +875,6 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 	ret = drm_modeset_lock(&crtc->cursor->mutex, &ctx);
 	if (ret)
 		goto out;
-	crtc->acquire_ctx = &ctx;
 
 	if (crtc->primary->fb == NULL) {
 		/* The framebuffer is currently unbound, presumably