drm/radeon: Add ability to get and change dpm state when radeon PX card is turned off

This fixing commit 4f2f203976964e267dc477de6648bdb3acd2b74b

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=76321

Signed-off-by: Pali Rohár <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>
Cc: [e-mail]

drivers/gpu/drm/radeon/radeon_pm.c

···
 	struct radeon_device *rdev = ddev->dev_private;
 	enum radeon_pm_state_type pm = rdev->pm.dpm.user_state;
 
-	if  ((rdev->flags & RADEON_IS_PX) &&
-	     (ddev->switch_power_state != DRM_SWITCH_POWER_ON))
-		return snprintf(buf, PAGE_SIZE, "off\n");
-
 	return snprintf(buf, PAGE_SIZE, "%s\n",
 			(pm == POWER_STATE_TYPE_BATTERY) ? "battery" :
 			(pm == POWER_STATE_TYPE_BALANCED) ? "balanced" : "performance");
···
 {
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct radeon_device *rdev = ddev->dev_private;
-
-	/* Can't set dpm state when the card is off */
-	if  ((rdev->flags & RADEON_IS_PX) &&
-	     (ddev->switch_power_state != DRM_SWITCH_POWER_ON))
-		return -EINVAL;
 
 	mutex_lock(&rdev->pm.mutex);
 	if (strncmp("battery", buf, strlen("battery")) == 0)
···
 		goto fail;
 	}
 	mutex_unlock(&rdev->pm.mutex);
-	radeon_pm_compute_clocks(rdev);
+
+	/* Can't set dpm state when the card is off */
+	if (!(rdev->flags & RADEON_IS_PX) ||
+	    (ddev->switch_power_state == DRM_SWITCH_POWER_ON))
+		radeon_pm_compute_clocks(rdev);
+
 fail:
 	return count;
 }