V4L/DVB (9036): uvcvideo: Fix control cache access when setting composite auto-update controls

Auto-update controls are never marked is loaded to prevent uvc_get_ctrl from
loading the control value from the cache. When setting a composite (mapped to
several V4L2 controls) auto-update UVC control, the driver updates the control
cache value before processing each V4L2 control, overwriting the previously
set V4L2 control.

This fixes the problem by marking all controls as loaded in uvc_set_ctrl
regardless of their type and resetting the loaded flag in uvc_commit_ctrl for
auto-update controls.
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_ctrl.c

@@ -837,7 +837,17 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
 
 	for (i = 0; i < entity->ncontrols; ++i) {
 		ctrl = &entity->controls[i];
-		if (ctrl->info == NULL || !ctrl->dirty)
+		if (ctrl->info == NULL)
+			continue;
+
+		/* Reset the loaded flag for auto-update controls that were
+		 * marked as loaded in uvc_ctrl_get/uvc_ctrl_set to prevent
+		 * uvc_ctrl_get from using the cached value.
+		 */
+		if (ctrl->info->flags & UVC_CONTROL_AUTO_UPDATE)
+			ctrl->loaded = 0;
+
+		if (!ctrl->dirty)
 			continue;
 
 		if (!rollback)
@@ -853,9 +863,6 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
 			       uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
 			       ctrl->info->size);
 
-		if ((ctrl->info->flags & UVC_CONTROL_GET_CUR) == 0)
-			ctrl->loaded = 0;
-
 		ctrl->dirty = 0;
 
 		if (ret < 0)
@@ -913,8 +920,7 @@ int uvc_ctrl_get(struct uvc_video_device *video,
 		if (ret < 0)
 			return ret;
 
-		if ((ctrl->info->flags & UVC_CONTROL_AUTO_UPDATE) == 0)
-			ctrl->loaded = 1;
+		ctrl->loaded = 1;
 	}
 
 	xctrl->value = uvc_get_le_value(
@@ -965,8 +971,7 @@ int uvc_ctrl_set(struct uvc_video_device *video,
 				return ret;
 		}
 
-		if ((ctrl->info->flags & UVC_CONTROL_AUTO_UPDATE) == 0)
-			ctrl->loaded = 1;
+		ctrl->loaded = 1;
 	}
 
 	if (!ctrl->dirty) {