drm/radeon/r5xx-r7xx: wait for the MC to settle after MC blackout

Some chips seem to need a little delay after blacking out
the MC before the requests actually stop. Stop DMAR errors
reported by Shuah Khan.

Reported-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/rv515.c b/drivers/gpu/drm/radeon/rv515.c
index 2bb6d0e84b3d94361546d06705c5d3252b7126bf..435ed35513643b868907716b9b4a231de4d0a58c 100644 (file)
--- a/drivers/gpu/drm/radeon/rv515.c
+++ b/drivers/gpu/drm/radeon/rv515.c
@@ -336,6 +336,8 @@ void rv515_mc_stop(struct radeon_device *rdev, struct rv515_mc_save *save)
                                WREG32(R600_CITF_CNTL, blackout);
                }
        }
+       /* wait for the MC to settle */
+       udelay(100);
 }
 
 void rv515_mc_resume(struct radeon_device *rdev, struct rv515_mc_save *save)