• Takashi Iwai's avatar
    ALSA: usb-audio: Fix bogus error messages for delay accounting · 1213a205
    Takashi Iwai authored
    The recent fix for the missing fine delayed time adjustment gives
    strange error messages at each start of the playback stream, such as
      delay: estimated 0, actual 352
      delay: estimated 353, actual 705
    
    These come from the sanity check in retire_playback_urb().  Before the
    stream is activated via start_endpoints(), a few silent packets have
    been already sent.  And at this point the delay account is still in
    the state as if the new packets are just queued, so the driver gets
    confused and spews the bogus error messages.
    
    For fixing the issue, we just need to check whether the received
    packet is valid, whether it's zero sized or not.
    Reported-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
    Cc: <stable@vger.kernel.org> [v3.5+]
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    1213a205
pcm.c 35.9 KB