Hi Guennadi,
Thank you for the patch.
On Friday, 28 July 2017 15:33:25 EEST Guennadi Liakhovetski wrote:
> When a command ends up in a STALL on the control pipe, use the Request
> Error Code control to provide a more precise error information to the
> user.
>
> Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@xxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_video.c | 59 ++++++++++++++++++++++++++++++++----
> 1 file changed, 53 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c
> b/drivers/media/usb/uvc/uvc_video.c index 006691e..887561b 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -34,15 +34,59 @@ static int __uvc_query_ctrl(struct uvc_device *dev, __u8
> query, __u8 unit, __u8 intfnum, __u8 cs, void *data, __u16 size,
> int timeout)
> {
> - __u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE;
> + __u8 type = USB_TYPE_CLASS | USB_RECIP_INTERFACE, tmp, error;
Please don't declare multiple variables per line, especially not after an
assignment.
> unsigned int pipe;
> + int ret;
>
> pipe = (query & 0x80) ? usb_rcvctrlpipe(dev->udev, 0)
> : usb_sndctrlpipe(dev->udev, 0);
> type |= (query & 0x80) ? USB_DIR_IN : USB_DIR_OUT;
>
> - return usb_control_msg(dev->udev, pipe, query, type, cs << 8,
> + ret = usb_control_msg(dev->udev, pipe, query, type, cs << 8,
> unit << 8 | intfnum, data, size, timeout);
> +
No need for a blank line here.
> + if (ret != -EPIPE)
> + return ret;
> +
> + tmp = *(u8 *)data;
Ouch, borrowing the passed data buffer sounds error-prone :-/ Wouldn't it be
better to kmalloc a buffer on demand, or possible allocate one in the
uvc_device structure and serialize the following code ? As it should be
invoked very infrequently that might not be a big issue.
> + pipe = usb_rcvctrlpipe(dev->udev, 0);
> + type = USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN;
> + ret = usb_control_msg(dev->udev, pipe, UVC_GET_CUR, type,
> + UVC_VC_REQUEST_ERROR_CODE_CONTROL << 8,
> + unit << 8 | intfnum, data, 1, timeout);
> + error = *(u8 *)data;
> + *(u8 *)data = tmp;
> +
> + if (ret < 0)
> + return ret;
> +
> + if (!ret)
> + return -EINVAL;
> +
> + uvc_trace(UVC_TRACE_CONTROL, "Control error %u\n", error);
> +
> + switch (error) {
> + case 0:
> + /* Cannot happen - we received a STALL */
> + return -EPIPE;
> + case 1: /* Not ready */
> + return -EAGAIN;
> + case 2: /* Wrong state */
> + return -EILSEQ;
> + case 3: /* Power */
> + return -EREMOTE;
> + case 4: /* Out of range */
> + return -ERANGE;
> + case 5: /* Invalid unit */
> + case 6: /* Invalid control */
> + case 7: /* Invalid Request */
> + case 8: /* Invalid value within range */
> + default: /* reserved or unknown */
> + break;
> + }
> +
> + return -EINVAL;
You can move this line to the default case.
What's your use case for this patch ? What error do you need to report, who do
you report it to, and how is it handled ?
> }
>
> static const char *uvc_query_name(__u8 query)
> @@ -80,7 +124,7 @@ int uvc_query_ctrl(struct uvc_device *dev, __u8 query,
> __u8 unit, uvc_printk(KERN_ERR, "Failed to query (%s) UVC control %u on "
> "unit %u: %d (exp. %u).\n", uvc_query_name(query), cs,
> unit, ret, size);
> - return -EIO;
> + return ret < 0 ? ret : -EIO;
> }
>
> return 0;
> @@ -203,13 +247,15 @@ static int uvc_get_video_ctrl(struct uvc_streaming
> *stream, uvc_warn_once(stream->dev, UVC_WARN_PROBE_DEF, "UVC non "
> "compliance - GET_DEF(PROBE) not supported. "
> "Enabling workaround.\n");
> - ret = -EIO;
> + if (ret >= 0)
> + ret = -EIO;
> goto out;
> } else if (ret != size) {
> uvc_printk(KERN_ERR, "Failed to query (%u) UVC %s control : "
> "%d (exp. %u).\n", query, probe ? "probe" : "commit",
> ret, size);
> - ret = -EIO;
> + if (ret >= 0)
> + ret = -EIO;
> goto out;
> }
>
> @@ -290,7 +336,8 @@ static int uvc_set_video_ctrl(struct uvc_streaming
> *stream, uvc_printk(KERN_ERR, "Failed to set UVC %s control : "
> "%d (exp. %u).\n", probe ? "probe" : "commit",
> ret, size);
> - ret = -EIO;
> + if (ret >= 0)
> + ret = -EIO;
> }
>
> kfree(data);
--
Regards,
Laurent Pinchart
