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    ASoC: samsung dma - Don't indicate support for pause/resume. · 57b2d688
    Dylan Reid 提交于
    The pause and resume operations indicate that the stream can be
    un-paused/resumed from the exact location they were paused/suspended.
    This is not true for this driver, the pause and suspend triggers share
    the same code path with stop, they flush all pending DMA transfers.
    This drops all pending samples.  The pause_release/resume triggers are
    the same as start, except that prepare won't be called beforehand,
    nothing will be enqueued to the DMA engine and nothing will happen (no
    audio).  Removing the pause flag will let apps know that it isn't
    supported.  Removing the resume flag will cause user space to call
    prepare and start instead of resume, so audio will continue playing when
    the system wakes up.
    
    Before removing the pause and resume flags, I tested this on an exynos
    5250, using 'aplay -i'. Pause/un-pause leads to silence followed by a
    write error.  Suspend/resume testing led to the same result.  Removing
    the two flags fixes suspend/resume (since snd_pcm_prepare is called
    again). And leads to a proper reporting of pause not supported.
    Signed-off-by: NDylan Reid <dgreid@chromium.org>
    Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
    Cc: stable@vger.kernel.org
    57b2d688
dma.c 11.0 KB