media: uvcvideo: Recover stalled ElGato devices

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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index d2eb9066e4dccda874a4067d043631e84a320242..503ef29211cac4055722df2238f519a99c6eb67e 100644 (file)
--- 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 +2122,21 @@ 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 (ret == -EPROTO &&
+           usb_match_one_id(stream->dev->intf, &elgato_cam_link_4k)) {
+               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");
+               usb_reset_device(stream->dev->udev);
+       }
+
        if (ret < 0)
                return ret;