• Takashi Iwai's avatar
    ALSA: hda - Force polling mode on CFL for fixing codec communication · a8d7bde2
    Takashi Iwai authored
    We've observed too long probe time with Coffee Lake (CFL) machines,
    and the likely cause is some communication problem between the
    HD-audio controller and the codec chips.  While the controller expects
    an IRQ wakeup for each codec response, it seems sometimes missing, and
    it takes one second for the controller driver to time out and read the
    response in the polling mode.
    
    Although we aren't sure about the real culprit yet, in this patch, we
    put a workaround by forcing the polling mode as default for CFL
    machines; the polling mode itself isn't too heavy, and much better
    than other workarounds initially suggested (e.g. disabling
    power-save), at least.
    
    Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199007
    Fixes: e79b0006 ("ALSA: hda - Add Coffelake PCI ID")
    Reported-and-tested-by: default avatarHui Wang <hui.wang@canonical.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    a8d7bde2
hda_intel.c 74.2 KB