drm/radeon: skip MC reset as it's probably not hung

The MC is mostly likely busy (e.g., display requests), not hung
so no need to reset it.  Doing an MC reset is tricky and not
particularly reliable.  Fixes hangs in certain cases.

Reported-by: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

4 files changed, 24 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 3c38ea46531c..305a657bf215 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2438,6 +2438,12 @@ static u32 evergreen_gpu_check_soft_reset(struct radeon_device *rdev)
         if (tmp & L2_BUSY)
                 reset_mask |= RADEON_RESET_VMC;
 
+        /* Skip MC reset as it's mostly likely not hung, just busy */
+        if (reset_mask & RADEON_RESET_MC) {
+                DRM_DEBUG("MC busy: 0x%08X, clearing.\n", reset_mask);
+                reset_mask &= ~RADEON_RESET_MC;
+        }
+
         return reset_mask;
 }
 
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index 7cead763be9e..d4c633e12863 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -1381,6 +1381,12 @@ static u32 cayman_gpu_check_soft_reset(struct radeon_device *rdev)
         if (tmp & L2_BUSY)
                 reset_mask |= RADEON_RESET_VMC;
 
+        /* Skip MC reset as it's mostly likely not hung, just busy */
+        if (reset_mask & RADEON_RESET_MC) {
+                DRM_DEBUG("MC busy: 0x%08X, clearing.\n", reset_mask);
+                reset_mask &= ~RADEON_RESET_MC;
+        }
+
         return reset_mask;
 }
 
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 6d4b5611daf4..0740db3fcd22 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -1394,6 +1394,12 @@ static u32 r600_gpu_check_soft_reset(struct radeon_device *rdev)
         if (r600_is_display_hung(rdev))
                 reset_mask |= RADEON_RESET_DISPLAY;
 
+        /* Skip MC reset as it's mostly likely not hung, just busy */
+        if (reset_mask & RADEON_RESET_MC) {
+                DRM_DEBUG("MC busy: 0x%08X, clearing.\n", reset_mask);
+                reset_mask &= ~RADEON_RESET_MC;
+        }
+
         return reset_mask;
 }
 
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index 80979ed951eb..9128120da044 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -2284,6 +2284,12 @@ static u32 si_gpu_check_soft_reset(struct radeon_device *rdev)
         if (tmp & L2_BUSY)
                 reset_mask |= RADEON_RESET_VMC;
 
+        /* Skip MC reset as it's mostly likely not hung, just busy */
+        if (reset_mask & RADEON_RESET_MC) {
+                DRM_DEBUG("MC busy: 0x%08X, clearing.\n", reset_mask);
+                reset_mask &= ~RADEON_RESET_MC;
+        }
+
         return reset_mask;
 }