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Commit 8e7a1dbc authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Mauro Carvalho Chehab
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media: uvcvideo: Handle control pipe protocol STALLs 



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. For example, if a camera is still busy processing a control,
when the same or an interrelated control set request arrives, the
camera can react with a STALL and then return the "Not ready" status
in response to a UVC_VC_REQUEST_ERROR_CODE_CONTROL command. With this
patch the user would then get an EBUSY error code instead of a
generic EPIPE.

Signed-off-by: default avatarGuennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 222964ea

drivers/media/usb/uvc/uvc_video.c

+46 −6
Original line number Original line Diff line number Diff line
@@ -73,17 +73,57 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, 
			u8 intfnum, u8 cs, void *data, u16 size)

			u8 intfnum, u8 cs, void *data, u16 size)

{

{

	int ret;

	int ret;

	u8 error;

	u8 tmp;





	ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,

	ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,

				UVC_CTRL_CONTROL_TIMEOUT);

				UVC_CTRL_CONTROL_TIMEOUT);

	if (ret != size) {

	if (likely(ret == size))

		uvc_printk(KERN_ERR, "Failed to query (%s) UVC control %u on "

		return 0;

			"unit %u: %d (exp. %u).\n", uvc_query_name(query), cs,



			unit, ret, size);

	uvc_printk(KERN_ERR,

		return -EIO;

		   "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",

		   uvc_query_name(query), cs, unit, ret, size);



	if (ret != -EPIPE)

		return ret;



	tmp = *(u8 *)data;



	ret = __uvc_query_ctrl(dev, UVC_GET_CUR, 0, intfnum,

			       UVC_VC_REQUEST_ERROR_CODE_CONTROL, data, 1,

			       UVC_CTRL_CONTROL_TIMEOUT);



	error = *(u8 *)data;

	*(u8 *)data = tmp;



	if (ret != 1)

		return ret < 0 ? ret : -EPIPE;



	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 -EBUSY;

	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 */

		return -EINVAL;

	default: /* reserved or unknown */

		break;

	}

	}





	return 0;

	return -EPIPE;

}

}





static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,

static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,