[media] uvcvideo: Fix V4L2 button controls that share the same UVC control
authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Fri, 11 May 2012 12:55:59 +0000 (09:55 -0300)
committerMauro Carvalho Chehab <mchehab@redhat.com>
Sun, 20 May 2012 13:41:18 +0000 (10:41 -0300)
commit6b363f9f97af10767e72a04c2a5cabfc32133cc4
tree32d455374f612d6f7b9416678c199733b11117cf
parente2b710bfde37dcc5e5c55fe09e640c1a218a81a2
[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>
drivers/media/video/uvc/uvc_ctrl.c