From 080de2e5be2d4b396b6792cde4cb2048fcdb4ce9 Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Mon, 16 Oct 2017 15:29:28 +0200
Subject: [PATCH] drm/atomic: Check for busy planes/connectors before setting the commit
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Git-commit: 080de2e5be2d4b396b6792cde4cb2048fcdb4ce9
Patch-mainline: v4.15-rc1
References: FATE#322643 bsc#1055900

We still want to fail with -EBUSY if a plane or connector is part of
a commit, even if it will be assigned to a new commit.

This closes a small hole left open where we should return -EBUSY.
It's not severe, because wait_for_dependencies and swap_state helpers
still block. But it should return -EBUSY and not stall.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 21a01abbe32a ("drm/atomic: Fix freeing connector/plane state too early by tracking commits, v3.")
Link: https://patchwork.freedesktop.org/patch/msgid/20171016132928.6498-2-maarten.lankhorst@linux.intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/drm_atomic_helper.c |   17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1772,16 +1772,16 @@ int drm_atomic_helper_setup_commit(struc
 	}
 
 	for_each_oldnew_connector_in_state(state, conn, old_conn_state, new_conn_state, i) {
-		/* commit tracked through new_crtc_state->commit, no need to do it explicitly */
-		if (new_conn_state->crtc)
-			continue;
-
 		/* Userspace is not allowed to get ahead of the previous
 		 * commit with nonblocking ones. */
 		if (nonblock && old_conn_state->commit &&
 		    !try_wait_for_completion(&old_conn_state->commit->flip_done))
 			return -EBUSY;
 
+		/* commit tracked through new_crtc_state->commit, no need to do it explicitly */
+		if (new_conn_state->crtc)
+			continue;
+
 		commit = crtc_or_fake_commit(state, old_conn_state->crtc);
 		if (!commit)
 			return -ENOMEM;
@@ -1790,17 +1790,16 @@ int drm_atomic_helper_setup_commit(struc
 	}
 
 	for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
-		/*
-		 * Unlike connectors, always track planes explicitly for
-		 * async pageflip support.
-		 */
-
 		/* Userspace is not allowed to get ahead of the previous
 		 * commit with nonblocking ones. */
 		if (nonblock && old_plane_state->commit &&
 		    !try_wait_for_completion(&old_plane_state->commit->flip_done))
 			return -EBUSY;
 
+		/*
+		 * Unlike connectors, always track planes explicitly for
+		 * async pageflip support.
+		 */
 		commit = crtc_or_fake_commit(state, new_plane_state->crtc ?: old_plane_state->crtc);
 		if (!commit)
 			return -ENOMEM;