The uvc_set_ctrl() calls don't write to the hardware. A failure at that point thus leaves the device in a clean state, with no control modified. Set the error_idx field to the count value to reflect that, as per the V4L2 specification. TRY_EXT_CTRLS is unchanged and the error_idx field must always be set to the failed control index in that case. Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> --- drivers/media/usb/uvc/uvc_v4l2.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 5eb8989..68d59b5 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -685,7 +685,8 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg) ret = uvc_ctrl_set(chain, ctrl); if (ret < 0) { uvc_ctrl_rollback(handle); - ctrls->error_idx = i; + ctrls->error_idx = cmd == VIDIOC_S_EXT_CTRLS + ? ctrls->count : i; return ret; } } -- 1.7.8.6 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html