Re: [alsa-devel] [PATCH v4] ALSA: usb: Work around CM6631 sample rate change bug

Torstein Hegge wrote:

• if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,

• 		   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
  

• 		   UAC2_CS_CONTROL_SAM_FREQ << 8,
  

• 		   snd_usb_ctrl_intf(chip) | (clock << 8),
  

• 		   data, sizeof(data))) < 0) {
  

• snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
  

• 	   dev->devnum, iface, fmt->altsetting);
  

• return err;
  

• }

This code requires that all devices allow reading the sample rate.

When you cannot read the current rate, just assume it needs to be set.

Regards, Clemens