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 Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> --- Recover stalled ElGato devices Just a resend of this hw fix. To: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> To: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Cc: linux-media@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> Cc: Yunke Cao <yunkec@xxxxxxxxxxxx> --- Changes in v2: - Remove info from lsusb - Link to v1: https://lore.kernel.org/r/20220920-resend-elgato-v1-0-8672a2380e3d@xxxxxxxxxxxx --- drivers/media/usb/uvc/uvc_video.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 170a008f4006..ad1762b66c4c 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -129,12 +129,12 @@ 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 +297,7 @@ 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 +2121,20 @@ 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; --- base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6 change-id: 20220920-resend-elgato-a845482bdd02 Best regards, -- Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
