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media: uvcvideo: Handle control pipe protocol STALLs

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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: Guennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Guennadi Liakhovetski 2018-05-08 11:07:44 -04:00 committed by Mauro Carvalho Chehab
parent 222964eaf2
commit 8e7a1dbc7b
1 changed files with 46 additions and 6 deletions
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52
drivers/media/usb/uvc/uvc_video.c
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@ -73,17 +73,57 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
u8 intfnum, u8 cs, void *data, u16 size)
{
int ret;
u8 error;
u8 tmp;
ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size,
UVC_CTRL_CONTROL_TIMEOUT);
if (ret != size) {
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;
if (likely(ret == size))
return 0;
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);
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,