[Intel-gfx] [PATCH] drm/i915: Handle error paths during watermark sanitization properly

[Matt Roper]

sanitize_watermarks() does not properly handle errors returned by
drm_atomic_helper_duplicate_state().  EDEADLK should trigger a modeset
backoff and retry; for other errors we need to drop locks before
returning.

Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
I think this might fix the problems that blew up the CI system recently.

 drivers/gpu/drm/i915/intel_display.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 391cc7f..fdff460 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15316,8 +15316,13 @@ retry:
 	}
 
 	state = drm_atomic_helper_duplicate_state(dev, &ctx);
-	if (WARN_ON(IS_ERR(state)))
-		return;
+	ret = PTR_ERR_OR_ZERO(state);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry;
+	} else if (WARN_ON(ret)) {
+		goto fail;
+	}
 
 	ret = intel_atomic_check(dev, state);
 	if (ret) {
@@ -15345,6 +15350,7 @@ retry:
 	}
 
 	drm_atomic_state_free(state);
+fail:
 	drm_modeset_drop_locks(&ctx);
 	drm_modeset_acquire_fini(&ctx);
 }
-- 
2.1.4