Felipe Balbi wrote:

100ms might not be enough for slower devices. Increasing timeout to 1000ms doesn't seem like overkill.

--- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -296,7 +296,7 @@ static int get_ctl_value_v1(struct usb_mixer_elem_info *cval, int request, int v if (snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), request, USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN, validx, snd_usb_ctrl_intf(chip) | (cval->id << 8),

• 		    buf, val_len, 100) >= val_len) {
  

• 		    buf, val_len, 1000) >= val_len) {
  

If the timeout for reading values needs to be increased, writing (in snd_usb_mixer_set_ctl_value) probably needs some attention too.

Regards, Clemens