[Intel-gfx] [PATCH v1.1 1/5] drm/i915: Handle return value in intel_pin_and_fence_fb_obj, v2.

[Maarten Lankhorst]

-EDEADLK has special meaning in atomic, but get_fence may call
i915_find_fence_reg which can return -EDEADLK.

This has special meaning in the atomic world, so convert the error
to -EBUSY for this case.

Changes since v1:
- Add comment in the code.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
Like this?

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index af0bcfee4771..11387f5ed681 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2395,8 +2395,20 @@ intel_pin_and_fence_fb_obj(struct drm_plane *plane,
 	 * a fence as the cost is not that onerous.
 	 */
 	ret = i915_gem_object_get_fence(obj);
-	if (ret)
+	if (ret) {
+		if (ret == -EDEADLK) {
+			/*
+			 * -EDEADLK means there are no free fences
+			 * and no pending flips.
+			 *
+			 * This is propagated to atomic, but it uses
+			 * -EDEADLK to force a locking recovery, so
+			 * change the returned error to -EBUSY.
+			 */
+			ret = -EBUSY;
+		}
 		goto err_unpin;
+	}
 
 	i915_gem_object_pin_fence(obj);