drm/radeon: disable force performance state when thermal state is active

If the thermal state is active, we are in the lowest performance level
to cool down the chip.  Don't let the user force it higher.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index 3ddd2c8..802e579 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -508,17 +508,21 @@
 	} else if (strncmp("auto", buf, strlen("auto")) == 0) {
 		level = RADEON_DPM_FORCED_LEVEL_AUTO;
 	} else {
-		mutex_unlock(&rdev->pm.mutex);
 		count = -EINVAL;
 		goto fail;
 	}
 	if (rdev->asic->dpm.force_performance_level) {
+		if (rdev->pm.dpm.thermal_active) {
+			count = -EINVAL;
+			goto fail;
+		}
 		ret = radeon_dpm_force_performance_level(rdev, level);
 		if (ret)
 			count = -EINVAL;
 	}
-	mutex_unlock(&rdev->pm.mutex);
 fail:
+	mutex_unlock(&rdev->pm.mutex);
+
 	return count;
 }