drm/i915: Handle return value in intel_pin_and_fence_fb_obj, v2.

-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@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index dc4812a493f55c91ea18d0f9bdaf339d2047caf6..16c8052f7eab0eab0141dc619d0ef5e92615f5fa 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2397,7 +2397,18 @@ 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 == -EDEADLK) {
+               /*
+                * -EDEADLK means there are no free fences
+                * 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;
+       } else if (ret)
                goto err_unpin;
 
        i915_gem_object_pin_fence(obj);