| Message ID | 20220920-resend-elgato-v3-0-57668054127f@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] media: uvcvideo: Recover stalled ElGato devices | expand |
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
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
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
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 --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;