drm/radeon/kms/pm: bail early if nothing's changing
If we aren't changing the power state, no need to take
locks and schedule fences, etc.
There seem to be lock ordering issues in the CP and
fence code in some cases; see bug 29140 below.
Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=29140
Possibly also:
https://bugzilla.kernel.org/show_bug.cgi?id=16581
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index 58038f5c..477ba67 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -226,6 +226,11 @@
{
int i;
+ /* no need to take locks, etc. if nothing's going to change */
+ if ((rdev->pm.requested_clock_mode_index == rdev->pm.current_clock_mode_index) &&
+ (rdev->pm.requested_power_state_index == rdev->pm.current_power_state_index))
+ return;
+
mutex_lock(&rdev->ddev->struct_mutex);
mutex_lock(&rdev->vram_mutex);
mutex_lock(&rdev->cp.mutex);