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SubjectRe: [PATCH v2 2/4] ALSA: hda: Rework snd_hdac_stream_reset() to use macros
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On 18/08/2022 15:15, Amadeusz Sławiński wrote:
> We can use existing macros to poll and update register values instead of
> open coding the functionality.
>
> Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
> Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
> ---
> sound/hda/hdac_stream.c | 26 ++++++--------------------
> 1 file changed, 6 insertions(+), 20 deletions(-)
>
> diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c
> index f3582012d22f..bdf6d4db6769 100644
> --- a/sound/hda/hdac_stream.c
> +++ b/sound/hda/hdac_stream.c
> @@ -165,7 +165,6 @@ EXPORT_SYMBOL_GPL(snd_hdac_stop_streams_and_chip);
> void snd_hdac_stream_reset(struct hdac_stream *azx_dev)
> {
> unsigned char val;
> - int timeout;
> int dma_run_state;
>
> snd_hdac_stream_clear(azx_dev);
> @@ -173,30 +172,17 @@ void snd_hdac_stream_reset(struct hdac_stream *azx_dev)
> dma_run_state = snd_hdac_stream_readb(azx_dev, SD_CTL) & SD_CTL_DMA_START;
>
> snd_hdac_stream_updateb(azx_dev, SD_CTL, 0, SD_CTL_STREAM_RESET);
> - udelay(3);
> - timeout = 300;
> - do {
> - val = snd_hdac_stream_readb(azx_dev, SD_CTL) &
> - SD_CTL_STREAM_RESET;
> - if (val)
> - break;
> - } while (--timeout);
> +
> + /* wait for hardware to report that the stream entered reset */
> + snd_hdac_stream_readb_poll(azx_dev, SD_CTL, val, (val & SD_CTL_STREAM_RESET), 3, 300);
>
> if (azx_dev->bus->dma_stop_delay && dma_run_state)
> udelay(azx_dev->bus->dma_stop_delay);
>
> - val &= ~SD_CTL_STREAM_RESET;
> - snd_hdac_stream_writeb(azx_dev, SD_CTL, val);
> - udelay(3);
> + snd_hdac_stream_updateb(azx_dev, SD_CTL, SD_CTL_STREAM_RESET, 0);
>
> - timeout = 300;
> - /* waiting for hardware to report that the stream is out of reset */
> - do {
> - val = snd_hdac_stream_readb(azx_dev, SD_CTL) &
> - SD_CTL_STREAM_RESET;
> - if (!val)
> - break;
> - } while (--timeout);
> + /* wait for hardware to report that the stream is out of reset */
> + snd_hdac_stream_readb_poll(azx_dev, SD_CTL, val, !(val & SD_CTL_STREAM_RESET), 3, 300);
>
> /* reset first position - may not be synced with hw at this time */
> if (azx_dev->posbuf)


HDA playback is failing on -next for various Tegra boards. Bisect is
point to this commit and reverting it fixes the problem. I was a bit
puzzled why this change is causing a problem, but looking closer there
is a difference between the previous code that was calling
snd_hdac_stream_readb() and the new code that is calling
snd_hdac_stream_readb_poll(). The function snd_hdac_stream_readb() calls
snd_hdac_aligned_mmio() is see if the device has an aligned MMIO which
Tegra does and then would call snd_hdac_aligned_read(). However, now the
code always call readb() and this is breaking Tegra.

So it is either necessary to update snd_hdac_stream_readb_poll() to
handle this or revert this change.

Cheers
Jon

--
nvpublic

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