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  • Koro Chen's avatar
    ALSA: pcm: Modify double acknowledged interrupts check condition · 13a98839
    Koro Chen authored
    Currently in snd_pcm_update_hw_ptr0 during interrupt,
    we consider there were double acknowledged interrupts when:
    1. HW reported pointer is smaller than expected, and
    2. Time from last update time (hdelta) is over half a buffer time.
    However, when HW reported pointer is only a few bytes smaller than
    expected, and when hdelta is just a little larger than half a buffer time
    (e.g. ping-pong buffer), it wrongly treats this IRQ as double acknowledged.
    The condition #2 uses jiffies, but jiffies is not high resolution
    since it is integer. We should consider jiffies inaccuracy.
    Signed-off-by: default avatarKoro Chen <>
    Signed-off-by: default avatarTakashi Iwai <>