Hi Laurent Thanks for your review On Mon, 5 Dec 2022 at 23:39, Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxx> > > 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 v3: > > - Add Reviewed-by: Sergey > > - Improve identation (Thanks Sergey!) > > - Link to v2: https://lore.kernel.org/r/20220920-resend-elgato-v2-0-06b48b3b486a@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 | 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@xxxxxxxxxxxxxxxx> > > > + } > > + > > if (ret < 0) > > return ret; > > > > > > --- > > base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6 > > change-id: 20220920-resend-elgato-a845482bdd02 > > -- > Regards, > > Laurent Pinchart -- Ricardo Ribalda
