diff mbox series

[v3] media: uvcvideo: Recover stalled ElGato devices

Message ID 20220920-resend-elgato-v3-0-57668054127f@chromium.org
State New
Headers
Series [v3] media: uvcvideo: Recover stalled ElGato devices |

Commit Message

Ricardo Ribalda Dec. 5, 2022, 12:53 p.m. UTC 
  Elgato Cam Link 4k can be in a stalled state if the resolution of
the external source has changed while the firmware initializes.
Once in this state, the device is useless until it receives a
USB reset. It has even been observed that the stalled state will
continue even after unplugging the device.

lsusb -v

Bus 002 Device 002: ID 0fd9:0066 Elgato Systems GmbH Cam Link 4K
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0         9
  idVendor           0x0fd9 Elgato Systems GmbH
  idProduct          0x0066
  bcdDevice            0.00
  iManufacturer           1 Elgato
  iProduct                2 Cam Link 4K
  iSerial                 4 0005AC52FE000
  bNumConfigurations      1

Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
Recover stalled ElGato devices

Just a resend of this hw fix.

To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Yunke Cao <yunkec@chromium.org>
---
Changes in v3:
- Add Reviewed-by: Sergey
- Improve identation (Thanks Sergey!)
- Link to v2: https://lore.kernel.org/r/20220920-resend-elgato-v2-0-06b48b3b486a@chromium.org

Changes in v2:
- Remove info from lsusb 
- Link to v1: https://lore.kernel.org/r/20220920-resend-elgato-v1-0-8672a2380e3d@chromium.org
---
 drivers/media/usb/uvc/uvc_video.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)


---
base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6
change-id: 20220920-resend-elgato-a845482bdd02

Best regards,

Comments

Laurent Pinchart Dec. 5, 2022, 10:38 p.m. UTC | #1 
Hi Ricardo,

Thank you for the patch.

On Mon, Dec 05, 2022 at 01:53:01PM +0100, Ricardo Ribalda wrote:
> Elgato Cam Link 4k can be in a stalled state if the resolution of
> the external source has changed while the firmware initializes.
> Once in this state, the device is useless until it receives a
> USB reset. It has even been observed that the stalled state will
> continue even after unplugging the device.

Why, ô, why :'-(

> lsusb -v
> 
> Bus 002 Device 002: ID 0fd9:0066 Elgato Systems GmbH Cam Link 4K
> Device Descriptor:
>   bLength                18
>   bDescriptorType         1
>   bcdUSB               3.00
>   bDeviceClass          239 Miscellaneous Device
>   bDeviceSubClass         2
>   bDeviceProtocol         1 Interface Association
>   bMaxPacketSize0         9
>   idVendor           0x0fd9 Elgato Systems GmbH
>   idProduct          0x0066
>   bcdDevice            0.00
>   iManufacturer           1 Elgato
>   iProduct                2 Cam Link 4K
>   iSerial                 4 0005AC52FE000
>   bNumConfigurations      1
> 
> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
> Recover stalled ElGato devices
> 
> Just a resend of this hw fix.
> 
> To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> To: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: linux-media@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
> Cc: Yunke Cao <yunkec@chromium.org>
> ---
> Changes in v3:
> - Add Reviewed-by: Sergey
> - Improve identation (Thanks Sergey!)
> - Link to v2: https://lore.kernel.org/r/20220920-resend-elgato-v2-0-06b48b3b486a@chromium.org
> 
> Changes in v2:
> - Remove info from lsusb 
> - Link to v1: https://lore.kernel.org/r/20220920-resend-elgato-v1-0-8672a2380e3d@chromium.org
> ---
>  drivers/media/usb/uvc/uvc_video.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 170a008f4006..a8323cf0e9f9 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -129,12 +129,13 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
>  	return -EPIPE;
>  }
>  
> +static const struct usb_device_id elgato_cam_link_4k = {
> +	USB_DEVICE(0x0fd9, 0x0066)
> +};
> +
>  static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
>  	struct uvc_streaming_control *ctrl)
>  {
> -	static const struct usb_device_id elgato_cam_link_4k = {
> -		USB_DEVICE(0x0fd9, 0x0066)
> -	};
>  	struct uvc_format *format = NULL;
>  	struct uvc_frame *frame = NULL;
>  	unsigned int i;
> @@ -297,7 +298,7 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream,
>  		dev_err(&stream->intf->dev,
>  			"Failed to query (%u) UVC %s control : %d (exp. %u).\n",
>  			query, probe ? "probe" : "commit", ret, size);
> -		ret = -EIO;
> +		ret = (ret == -EPROTO) ? -EPROTO : -EIO;

This will change the error returned by VIDIOC_S_FMT and VIDIOC_TRY_FMT,
but I don't think that will cause issues.

>  		goto out;
>  	}
>  
> @@ -2121,6 +2122,20 @@ int uvc_video_init(struct uvc_streaming *stream)
>  	 * request on the probe control, as required by the UVC specification.
>  	 */
>  	ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
> +
> +	/*
> +	 * Elgato Cam Link 4k can be in a stalled state if the resolution of
> +	 * the external source has changed while the firmware initializes.
> +	 * Once in this state, the device is useless until it receives a
> +	 * USB reset. It has even been observed that the stalled state will
> +	 * continue even after unplugging the device.
> +	 */
> +	if (usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k) &&
> +	    (ret == -EPROTO)) {

I'd swap the tests, as the second one is cheaper. You also don't need
the inner parentheses.

> +		usb_reset_device(stream->dev->udev);
> +		dev_err(&stream->intf->dev, "Restarting Elgato Cam Link 4K\n");

I would also swap those two lines, if an error occurs when resetting the
device, it's good to have the "restarting" message printed first.

If I understand this correctly, probe will still fail, and the user will
have to unplug and replug the device to fix this, right ? If so I'd
expand the error message, maybe something along those lines:

		dev_err(&stream->intf->dev, "Elgato Cam Link 4K firmware crash detected\n");
		dev_err(&stream->intf->dev, "Resetting the device, unplug and replug to recover\n");

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +	}
> +
>  	if (ret < 0)
>  		return ret;
>  
> 
> ---
> base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6
> change-id: 20220920-resend-elgato-a845482bdd02
Ricardo Ribalda Dec. 5, 2022, 10:45 p.m. UTC | #2 
Hi Laurent

Thanks for your review

On Mon, 5 Dec 2022 at 23:39, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.
>
> On Mon, Dec 05, 2022 at 01:53:01PM +0100, Ricardo Ribalda wrote:
> > Elgato Cam Link 4k can be in a stalled state if the resolution of
> > the external source has changed while the firmware initializes.
> > Once in this state, the device is useless until it receives a
> > USB reset. It has even been observed that the stalled state will
> > continue even after unplugging the device.
>
> Why, ô, why :'-(
>
> > lsusb -v
> >
> > Bus 002 Device 002: ID 0fd9:0066 Elgato Systems GmbH Cam Link 4K
> > Device Descriptor:
> >   bLength                18
> >   bDescriptorType         1
> >   bcdUSB               3.00
> >   bDeviceClass          239 Miscellaneous Device
> >   bDeviceSubClass         2
> >   bDeviceProtocol         1 Interface Association
> >   bMaxPacketSize0         9
> >   idVendor           0x0fd9 Elgato Systems GmbH
> >   idProduct          0x0066
> >   bcdDevice            0.00
> >   iManufacturer           1 Elgato
> >   iProduct                2 Cam Link 4K
> >   iSerial                 4 0005AC52FE000
> >   bNumConfigurations      1
> >
> > Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> > Recover stalled ElGato devices
> >
> > Just a resend of this hw fix.
> >
> > To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > To: Mauro Carvalho Chehab <mchehab@kernel.org>
> > Cc: linux-media@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
> > Cc: Yunke Cao <yunkec@chromium.org>
> > ---
> > Changes in v3:
> > - Add Reviewed-by: Sergey
> > - Improve identation (Thanks Sergey!)
> > - Link to v2: https://lore.kernel.org/r/20220920-resend-elgato-v2-0-06b48b3b486a@chromium.org
> >
> > Changes in v2:
> > - Remove info from lsusb
> > - Link to v1: https://lore.kernel.org/r/20220920-resend-elgato-v1-0-8672a2380e3d@chromium.org
> > ---
> >  drivers/media/usb/uvc/uvc_video.c | 23 +++++++++++++++++++----
> >  1 file changed, 19 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > index 170a008f4006..a8323cf0e9f9 100644
> > --- a/drivers/media/usb/uvc/uvc_video.c
> > +++ b/drivers/media/usb/uvc/uvc_video.c
> > @@ -129,12 +129,13 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
> >       return -EPIPE;
> >  }
> >
> > +static const struct usb_device_id elgato_cam_link_4k = {
> > +     USB_DEVICE(0x0fd9, 0x0066)
> > +};
> > +
> >  static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
> >       struct uvc_streaming_control *ctrl)
> >  {
> > -     static const struct usb_device_id elgato_cam_link_4k = {
> > -             USB_DEVICE(0x0fd9, 0x0066)
> > -     };
> >       struct uvc_format *format = NULL;
> >       struct uvc_frame *frame = NULL;
> >       unsigned int i;
> > @@ -297,7 +298,7 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream,
> >               dev_err(&stream->intf->dev,
> >                       "Failed to query (%u) UVC %s control : %d (exp. %u).\n",
> >                       query, probe ? "probe" : "commit", ret, size);
> > -             ret = -EIO;
> > +             ret = (ret == -EPROTO) ? -EPROTO : -EIO;
>
> This will change the error returned by VIDIOC_S_FMT and VIDIOC_TRY_FMT,
> but I don't think that will cause issues.
>
> >               goto out;
> >       }
> >
> > @@ -2121,6 +2122,20 @@ int uvc_video_init(struct uvc_streaming *stream)
> >        * request on the probe control, as required by the UVC specification.
> >        */
> >       ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
> > +
> > +     /*
> > +      * Elgato Cam Link 4k can be in a stalled state if the resolution of
> > +      * the external source has changed while the firmware initializes.
> > +      * Once in this state, the device is useless until it receives a
> > +      * USB reset. It has even been observed that the stalled state will
> > +      * continue even after unplugging the device.
> > +      */
> > +     if (usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k) &&
> > +         (ret == -EPROTO)) {
>
> I'd swap the tests, as the second one is cheaper. You also don't need
> the inner parentheses.
>
> > +             usb_reset_device(stream->dev->udev);
> > +             dev_err(&stream->intf->dev, "Restarting Elgato Cam Link 4K\n");
>
> I would also swap those two lines, if an error occurs when resetting the
> device, it's good to have the "restarting" message printed first.
>
> If I understand this correctly, probe will still fail, and the user will
> have to unplug and replug the device to fix this, right ? If so I'd
> expand the error message, maybe something along those lines:

I kind of recall that it was not needed to replug the device. Will
test on real hardware to confirm.


>
>                 dev_err(&stream->intf->dev, "Elgato Cam Link 4K firmware crash detected\n");
>                 dev_err(&stream->intf->dev, "Resetting the device, unplug and replug to recover\n");
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> > +     }
> > +
> >       if (ret < 0)
> >               return ret;
> >
> >
> > ---
> > base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6
> > change-id: 20220920-resend-elgato-a845482bdd02
>
> --
> Regards,
>
> Laurent Pinchart
Laurent Pinchart Dec. 5, 2022, 10:55 p.m. UTC | #3 
Hi Ricardo,

On Mon, Dec 05, 2022 at 11:45:43PM +0100, Ricardo Ribalda wrote:
> On Mon, 5 Dec 2022 at 23:39, Laurent Pinchart wrote:
> > On Mon, Dec 05, 2022 at 01:53:01PM +0100, Ricardo Ribalda wrote:
> > > Elgato Cam Link 4k can be in a stalled state if the resolution of
> > > the external source has changed while the firmware initializes.
> > > Once in this state, the device is useless until it receives a
> > > USB reset. It has even been observed that the stalled state will
> > > continue even after unplugging the device.
> >
> > Why, ô, why :'-(
> >
> > > lsusb -v
> > >
> > > Bus 002 Device 002: ID 0fd9:0066 Elgato Systems GmbH Cam Link 4K
> > > Device Descriptor:
> > >   bLength                18
> > >   bDescriptorType         1
> > >   bcdUSB               3.00
> > >   bDeviceClass          239 Miscellaneous Device
> > >   bDeviceSubClass         2
> > >   bDeviceProtocol         1 Interface Association
> > >   bMaxPacketSize0         9
> > >   idVendor           0x0fd9 Elgato Systems GmbH
> > >   idProduct          0x0066
> > >   bcdDevice            0.00
> > >   iManufacturer           1 Elgato
> > >   iProduct                2 Cam Link 4K
> > >   iSerial                 4 0005AC52FE000
> > >   bNumConfigurations      1
> > >
> > > Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > > ---
> > > Recover stalled ElGato devices
> > >
> > > Just a resend of this hw fix.
> > >
> > > To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > To: Mauro Carvalho Chehab <mchehab@kernel.org>
> > > Cc: linux-media@vger.kernel.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
> > > Cc: Yunke Cao <yunkec@chromium.org>
> > > ---
> > > Changes in v3:
> > > - Add Reviewed-by: Sergey
> > > - Improve identation (Thanks Sergey!)
> > > - Link to v2: https://lore.kernel.org/r/20220920-resend-elgato-v2-0-06b48b3b486a@chromium.org
> > >
> > > Changes in v2:
> > > - Remove info from lsusb
> > > - Link to v1: https://lore.kernel.org/r/20220920-resend-elgato-v1-0-8672a2380e3d@chromium.org
> > > ---
> > >  drivers/media/usb/uvc/uvc_video.c | 23 +++++++++++++++++++----
> > >  1 file changed, 19 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > > index 170a008f4006..a8323cf0e9f9 100644
> > > --- a/drivers/media/usb/uvc/uvc_video.c
> > > +++ b/drivers/media/usb/uvc/uvc_video.c
> > > @@ -129,12 +129,13 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
> > >       return -EPIPE;
> > >  }
> > >
> > > +static const struct usb_device_id elgato_cam_link_4k = {
> > > +     USB_DEVICE(0x0fd9, 0x0066)
> > > +};
> > > +
> > >  static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
> > >       struct uvc_streaming_control *ctrl)
> > >  {
> > > -     static const struct usb_device_id elgato_cam_link_4k = {
> > > -             USB_DEVICE(0x0fd9, 0x0066)
> > > -     };
> > >       struct uvc_format *format = NULL;
> > >       struct uvc_frame *frame = NULL;
> > >       unsigned int i;
> > > @@ -297,7 +298,7 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream,
> > >               dev_err(&stream->intf->dev,
> > >                       "Failed to query (%u) UVC %s control : %d (exp. %u).\n",
> > >                       query, probe ? "probe" : "commit", ret, size);
> > > -             ret = -EIO;
> > > +             ret = (ret == -EPROTO) ? -EPROTO : -EIO;
> >
> > This will change the error returned by VIDIOC_S_FMT and VIDIOC_TRY_FMT,
> > but I don't think that will cause issues.
> >
> > >               goto out;
> > >       }
> > >
> > > @@ -2121,6 +2122,20 @@ int uvc_video_init(struct uvc_streaming *stream)
> > >        * request on the probe control, as required by the UVC specification.
> > >        */
> > >       ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
> > > +
> > > +     /*
> > > +      * Elgato Cam Link 4k can be in a stalled state if the resolution of
> > > +      * the external source has changed while the firmware initializes.
> > > +      * Once in this state, the device is useless until it receives a
> > > +      * USB reset. It has even been observed that the stalled state will
> > > +      * continue even after unplugging the device.
> > > +      */
> > > +     if (usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k) &&
> > > +         (ret == -EPROTO)) {
> >
> > I'd swap the tests, as the second one is cheaper. You also don't need
> > the inner parentheses.
> >
> > > +             usb_reset_device(stream->dev->udev);
> > > +             dev_err(&stream->intf->dev, "Restarting Elgato Cam Link 4K\n");
> >
> > I would also swap those two lines, if an error occurs when resetting the
> > device, it's good to have the "restarting" message printed first.
> >
> > If I understand this correctly, probe will still fail, and the user will
> > have to unplug and replug the device to fix this, right ? If so I'd
> > expand the error message, maybe something along those lines:
> 
> I kind of recall that it was not needed to replug the device. Will
> test on real hardware to confirm.

How does it get reprobed then ? By unloading and reloading the driver
(or unbinding and rebinding the device through sysfs) ?

> >                 dev_err(&stream->intf->dev, "Elgato Cam Link 4K firmware crash detected\n");
> >                 dev_err(&stream->intf->dev, "Resetting the device, unplug and replug to recover\n");
> >
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >
> > > +     }
> > > +
> > >       if (ret < 0)
> > >               return ret;
> > >
> > >
> > > ---
> > > base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6
> > > change-id: 20220920-resend-elgato-a845482bdd02
Ricardo Ribalda Dec. 5, 2022, 11:09 p.m. UTC | #4 
On Mon, 5 Dec 2022 at 23:55, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> On Mon, Dec 05, 2022 at 11:45:43PM +0100, Ricardo Ribalda wrote:
> > On Mon, 5 Dec 2022 at 23:39, Laurent Pinchart wrote:
> > > On Mon, Dec 05, 2022 at 01:53:01PM +0100, Ricardo Ribalda wrote:
> > > > Elgato Cam Link 4k can be in a stalled state if the resolution of
> > > > the external source has changed while the firmware initializes.
> > > > Once in this state, the device is useless until it receives a
> > > > USB reset. It has even been observed that the stalled state will
> > > > continue even after unplugging the device.
> > >
> > > Why, ô, why :'-(
> > >
> > > > lsusb -v
> > > >
> > > > Bus 002 Device 002: ID 0fd9:0066 Elgato Systems GmbH Cam Link 4K
> > > > Device Descriptor:
> > > >   bLength                18
> > > >   bDescriptorType         1
> > > >   bcdUSB               3.00
> > > >   bDeviceClass          239 Miscellaneous Device
> > > >   bDeviceSubClass         2
> > > >   bDeviceProtocol         1 Interface Association
> > > >   bMaxPacketSize0         9
> > > >   idVendor           0x0fd9 Elgato Systems GmbH
> > > >   idProduct          0x0066
> > > >   bcdDevice            0.00
> > > >   iManufacturer           1 Elgato
> > > >   iProduct                2 Cam Link 4K
> > > >   iSerial                 4 0005AC52FE000
> > > >   bNumConfigurations      1
> > > >
> > > > Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > > > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > > > ---
> > > > Recover stalled ElGato devices
> > > >
> > > > Just a resend of this hw fix.
> > > >
> > > > To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > To: Mauro Carvalho Chehab <mchehab@kernel.org>
> > > > Cc: linux-media@vger.kernel.org
> > > > Cc: linux-kernel@vger.kernel.org
> > > > Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
> > > > Cc: Yunke Cao <yunkec@chromium.org>
> > > > ---
> > > > Changes in v3:
> > > > - Add Reviewed-by: Sergey
> > > > - Improve identation (Thanks Sergey!)
> > > > - Link to v2: https://lore.kernel.org/r/20220920-resend-elgato-v2-0-06b48b3b486a@chromium.org
> > > >
> > > > Changes in v2:
> > > > - Remove info from lsusb
> > > > - Link to v1: https://lore.kernel.org/r/20220920-resend-elgato-v1-0-8672a2380e3d@chromium.org
> > > > ---
> > > >  drivers/media/usb/uvc/uvc_video.c | 23 +++++++++++++++++++----
> > > >  1 file changed, 19 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > > > index 170a008f4006..a8323cf0e9f9 100644
> > > > --- a/drivers/media/usb/uvc/uvc_video.c
> > > > +++ b/drivers/media/usb/uvc/uvc_video.c
> > > > @@ -129,12 +129,13 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
> > > >       return -EPIPE;
> > > >  }
> > > >
> > > > +static const struct usb_device_id elgato_cam_link_4k = {
> > > > +     USB_DEVICE(0x0fd9, 0x0066)
> > > > +};
> > > > +
> > > >  static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
> > > >       struct uvc_streaming_control *ctrl)
> > > >  {
> > > > -     static const struct usb_device_id elgato_cam_link_4k = {
> > > > -             USB_DEVICE(0x0fd9, 0x0066)
> > > > -     };
> > > >       struct uvc_format *format = NULL;
> > > >       struct uvc_frame *frame = NULL;
> > > >       unsigned int i;
> > > > @@ -297,7 +298,7 @@ static int uvc_get_video_ctrl(struct uvc_streaming *stream,
> > > >               dev_err(&stream->intf->dev,
> > > >                       "Failed to query (%u) UVC %s control : %d (exp. %u).\n",
> > > >                       query, probe ? "probe" : "commit", ret, size);
> > > > -             ret = -EIO;
> > > > +             ret = (ret == -EPROTO) ? -EPROTO : -EIO;
> > >
> > > This will change the error returned by VIDIOC_S_FMT and VIDIOC_TRY_FMT,
> > > but I don't think that will cause issues.
> > >
> > > >               goto out;
> > > >       }
> > > >
> > > > @@ -2121,6 +2122,20 @@ int uvc_video_init(struct uvc_streaming *stream)
> > > >        * request on the probe control, as required by the UVC specification.
> > > >        */
> > > >       ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
> > > > +
> > > > +     /*
> > > > +      * Elgato Cam Link 4k can be in a stalled state if the resolution of
> > > > +      * the external source has changed while the firmware initializes.
> > > > +      * Once in this state, the device is useless until it receives a
> > > > +      * USB reset. It has even been observed that the stalled state will
> > > > +      * continue even after unplugging the device.
> > > > +      */
> > > > +     if (usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k) &&
> > > > +         (ret == -EPROTO)) {
> > >
> > > I'd swap the tests, as the second one is cheaper. You also don't need
> > > the inner parentheses.
> > >
> > > > +             usb_reset_device(stream->dev->udev);
> > > > +             dev_err(&stream->intf->dev, "Restarting Elgato Cam Link 4K\n");
> > >
> > > I would also swap those two lines, if an error occurs when resetting the
> > > device, it's good to have the "restarting" message printed first.
> > >
> > > If I understand this correctly, probe will still fail, and the user will
> > > have to unplug and replug the device to fix this, right ? If so I'd
> > > expand the error message, maybe something along those lines:
> >
> > I kind of recall that it was not needed to replug the device. Will
> > test on real hardware to confirm.
>
> How does it get reprobed then ? By unloading and reloading the driver
> (or unbinding and rebinding the device through sysfs) ?

Just went through the internal bug report. We were rebinding the
driver during the test.

Will add the "unplug-replug" message

Thanks!



>
> > >                 dev_err(&stream->intf->dev, "Elgato Cam Link 4K firmware crash detected\n");
> > >                 dev_err(&stream->intf->dev, "Resetting the device, unplug and replug to recover\n");
> > >
> > > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > >
> > > > +     }
> > > > +
> > > >       if (ret < 0)
> > > >               return ret;
> > > >
> > > >
> > > > ---
> > > > base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6
> > > > change-id: 20220920-resend-elgato-a845482bdd02
>
> --
> Regards,
>
> Laurent Pinchart
diff mbox series

Patch

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 170a008f4006..a8323cf0e9f9 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -129,12 +129,13 @@  int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
 	return -EPIPE;
 }
 
+static const struct usb_device_id elgato_cam_link_4k = {
+	USB_DEVICE(0x0fd9, 0x0066)
+};
+
 static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
 	struct uvc_streaming_control *ctrl)
 {
-	static const struct usb_device_id elgato_cam_link_4k = {
-		USB_DEVICE(0x0fd9, 0x0066)
-	};
 	struct uvc_format *format = NULL;
 	struct uvc_frame *frame = NULL;
 	unsigned int i;
@@ -297,7 +298,7 @@  static int uvc_get_video_ctrl(struct uvc_streaming *stream,
 		dev_err(&stream->intf->dev,
 			"Failed to query (%u) UVC %s control : %d (exp. %u).\n",
 			query, probe ? "probe" : "commit", ret, size);
-		ret = -EIO;
+		ret = (ret == -EPROTO) ? -EPROTO : -EIO;
 		goto out;
 	}
 
@@ -2121,6 +2122,20 @@  int uvc_video_init(struct uvc_streaming *stream)
 	 * request on the probe control, as required by the UVC specification.
 	 */
 	ret = uvc_get_video_ctrl(stream, probe, 1, UVC_GET_CUR);
+
+	/*
+	 * Elgato Cam Link 4k can be in a stalled state if the resolution of
+	 * the external source has changed while the firmware initializes.
+	 * Once in this state, the device is useless until it receives a
+	 * USB reset. It has even been observed that the stalled state will
+	 * continue even after unplugging the device.
+	 */
+	if (usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k) &&
+	    (ret == -EPROTO)) {
+		usb_reset_device(stream->dev->udev);
+		dev_err(&stream->intf->dev, "Restarting Elgato Cam Link 4K\n");
+	}
+
 	if (ret < 0)
 		return ret;