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  • Takashi Iwai's avatar
    ALSA: pcm - Fix drain behavior in non-blocking mode · 4cdc115f
    Takashi Iwai authored
    The current PCM core has the following problems regarding PCM draining
    in non-blocking mode:
    - the current f_flags isn't checked in snd_pcm_drain(), thus changing
      the mode dynamically via snd_pcm_nonblock() after open doesn't work.
    - calling drain in non-blocking mode just return -EAGAIN error, but
      doesn't provide any way to sync with draining.
    This patch fixes these issues.
    - check file->f_flags in snd_pcm_drain() properly
    - when O_NONBLOCK is set, PCM core sets the stream(s) to DRAIN state
      but quits ioctl immediately without waiting the whole drain; the
      caller can sync the drain manually via poll()
    Signed-off-by: default avatarTakashi Iwai <>