• Takashi Iwai's avatar
    ALSA: usb-audio: Workaround for clock setup on TEAC devices · 5ce0b06a
    Takashi Iwai authored
    Maris reported that TEAC UD-501 (0644:8043) doesn't work with the
    typical "clock source 41 is not valid, cannot use" errors on the
    recent kernels.  The currently known workaround so far is to restore
    (partially) what we've done unconditionally at the clock setup;
    namely, re-setup the USB interface immediately after the clock is
    changed.  This patch re-introduces the behavior conditionally for TEAC
    devices.
    
    Further notes:
    - The USB interface shall be set later in
      snd_usb_endpoint_configure(), but this seems to be too late.
    - Even calling  usb_set_interface() right after
      sne_usb_init_sample_rate() doesn't help; so this must be related
      with the clock validation, too.
    - The device may still spew the "clock source 41 is not valid" error
      at the first clock setup.  This seems happening at the very first
      try of clock setup, but it disappears at later attempts.
      The error is likely harmless because the driver retries the clock
      setup (such an error is more or less expected on some devices).
    
    Fixes: bf6313a0 ("ALSA: usb-audio: Refactor endpoint management")
    Reported-and-tested-by: default avatarMaris Abele <maris7abele@gmail.com>
    Cc: <stable@vger.kernel.org>
    Link: https://lore.kernel.org/r/20220521064627.29292-1-tiwai@suse.deSigned-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    5ce0b06a
clock.c 16 KB