Commit 6b363f9f authored May 11, 2012 by Laurent Pinchart Committed by Mauro Carvalho Chehab May 20, 2012

[media] uvcvideo: Fix V4L2 button controls that share the same UVC control

The Logitech pan/tilt reset UVC control contains two V4L2 button
controls to reset pan and tilt. As the UVC control is not marked as
auto-update, the button bits are set but never reset. A pan reset that
follows a tilt reset would thus reset both pan and tilt.

Fix this by not caching the control value of write-only controls. All
standard UVC controls are either readable or auto-update, so this will
not cause any regression and will not result in extra USB requests.

Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

parent e2b710bf

drivers/media/video/uvc/uvc_ctrl.c

+5 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1351,9 +1351,12 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,

	/* Reset the loaded flag for auto-update controls that were		/* Reset the loaded flag for auto-update controls that were
	* marked as loaded in uvc_ctrl_get/uvc_ctrl_set to prevent		* marked as loaded in uvc_ctrl_get/uvc_ctrl_set to prevent
	* uvc_ctrl_get from using the cached value.		* uvc_ctrl_get from using the cached value, and for write-only
			* controls to prevent uvc_ctrl_set from setting bits not
			* explicitly set by the user.
	*/		*/
	if (ctrl->info.flags & UVC_CTRL_FLAG_AUTO_UPDATE)		if (ctrl->info.flags & UVC_CTRL_FLAG_AUTO_UPDATE \|\|
			!(ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR))
	ctrl->loaded = 0;		ctrl->loaded = 0;

	if (!ctrl->dirty)		if (!ctrl->dirty)