drm/i915: disable FBC when more than one pipe is active

We're really supposed to do this to avoid trouble with underflows when
multiple planes are active.

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=26987.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: fangxun <xunx.fang@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index aee83fa178f6..9214119c0154 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -605,6 +605,9 @@ static int i915_fbc_status(struct seq_file *m, void *unused)
                 case FBC_NOT_TILED:
                         seq_printf(m, "scanout buffer not tiled");
                         break;
+                case FBC_MULTIPLE_PIPES:
+                        seq_printf(m, "multiple pipes are enabled");
+                        break;
                 default:
                         seq_printf(m, "unknown reason");
                 }