[PATCH] drm: Fix locking in drm_atomic_helper_resume

[Daniel Vetter]

In the conversion to drop drm_modeset_lock_all and the magic implicit
context I failed to realize that _resume starts out with a pile of
state copies, but not with the locks. And hence drm_atomic_commit
won't grab these for us.

Cc: Jyri Sarha <jsarha at ti.com>
Fixes: a5b8444e289c ("drm/atomic-helper: remove modeset_lock_all from helper_resume")
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Sean Paul <seanpaul at chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
Needs to be applied to drm-misc-fixes for 4.12.
-Daniel
---
 drivers/gpu/drm/drm_atomic_helper.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index af07368846e0..a61291c29567 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -2669,7 +2669,12 @@ int drm_atomic_helper_resume(struct drm_device *dev,
 
 	drm_modeset_acquire_init(&ctx, 0);
 	while (1) {
+		err = drm_modeset_lock_all_ctx(dev, &ctx);
+		if (err)
+			goto out;
+
 		err = drm_atomic_helper_commit_duplicated_state(state, &ctx);
+out:
 		if (err != -EDEADLK)
 			break;
 
-- 
2.11.0