From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Tue, 11 Jul 2017 16:33:12 +0200
Subject: drm/vc4: Handle drm_atomic_helper_swap_state failure
Git-commit: d68bc0e75a7194a3d7e738705a7d54e66a06d75f
Patch-mainline: v4.14-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

drm_atomic_helper_swap_state() will be changed to interruptible waiting
in the next few commits, so all drivers have to be changed to handling
failure.

VC4 has its own nonblocking modeset tracking through the vc4->async_modeset
semaphore, so it doesn't need to stall in swap_state. Pass stall = false
and BUG_ON when it returns an error. This should never happen for !stall.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/20170711143314.2148-11-maarten.lankhorst@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/vc4/vc4_kms.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -126,7 +126,7 @@ static int vc4_atomic_commit(struct drm_
 	 * the software side now.
 	 */
 
-	drm_atomic_helper_swap_state(state, true);
+	BUG_ON(drm_atomic_helper_swap_state(state, false) < 0);
 
 	/*
 	 * Everything below can be run asynchronously without the need to grab