[Intel-gfx] [PATCH] drm/i915/fbc: only update no_fbc_reason when active

[Daniel Vetter]

In our snb farm in CI we have plenty of underruns, but not enough
stolen memory to enable fbc. Which means every time there's an
underrun the no_fbc_reason swichtes to something that makes
kms_frontbuffer_tracking fail instead of skip, adding massive amounts
of additional noise to igt test runs.

Make sure we don't try to disable fbc when it's off already.

Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/i915/intel_fbc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index 860b8c26d29b..4015b1e716e5 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -1216,7 +1216,7 @@ static void intel_fbc_underrun_work_fn(struct work_struct *work)
 	mutex_lock(&fbc->lock);
 
 	/* Maybe we were scheduled twice. */
-	if (fbc->underrun_detected)
+	if (fbc->underrun_detected || !fbc->enabled)
 		goto out;
 
 	DRM_DEBUG_KMS("Disabling FBC due to FIFO underrun.\n");
-- 
2.13.3