From: Lars-Peter Clausen <lars@metafoo.de>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: alsa-devel@alsa-project.org, nsekhar@ti.com,
Liam Girdwood <lgirdwood@gmail.com>, Jyri Sarha <jsarha@ti.com>,
zonque@gmail.com, Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH v2 3/4] ASoC: davinci-mcasp: Constraint on the period and buffer size based on FIFO usage
Date: Sun, 16 Mar 2014 12:18:59 +0100 [thread overview]
Message-ID: <532588A3.4050301@metafoo.de> (raw)
In-Reply-To: <1394808168-32608-4-git-send-email-peter.ujfalusi@ti.com>
On 03/14/2014 03:42 PM, Peter Ujfalusi wrote:
> We need to place constraint on the period and buffer size if the read
> or write AFIFO is enabled and it is configured for more than one word
> otherwise the DMA will fail in buffer configuration where the sizes
> are not aligned with the requested FIFO configuration.
>
> Some application (like mplayer) needs the constraint placed on the
> buffer size as well. If only period size is constrained they might
> fail to figure out the allowed buffer configuration.
Hm... the sound like there is still a bug somewhere. We constrain the buffer
size to be a multiple of the period size. If the period size is constraint
to be a multiple of a constant then the buffer size should automatically be
constrained to be a multiple of constant * period count. And just
constraining the buffer size to be a multiple of the burst size still allows
buffer sizes that are not a multiple of burst size * period count.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
> sound/soc/davinci/davinci-mcasp.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
> index a01ae97c90aa..3ca6e8c4568a 100644
> --- a/sound/soc/davinci/davinci-mcasp.c
> +++ b/sound/soc/davinci/davinci-mcasp.c
> @@ -720,6 +720,7 @@ static int davinci_mcasp_startup(struct snd_pcm_substream *substream,
> struct snd_soc_dai *dai)
> {
> struct davinci_mcasp *mcasp = snd_soc_dai_get_drvdata(dai);
> + int afifo_numevt;
>
> if (mcasp->version == MCASP_VERSION_4)
> snd_soc_dai_set_dma_data(dai, substream,
> @@ -727,6 +728,21 @@ static int davinci_mcasp_startup(struct snd_pcm_substream *substream,
> else
> snd_soc_dai_set_dma_data(dai, substream, mcasp->dma_params);
>
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + afifo_numevt = mcasp->txnumevt;
> + else
> + afifo_numevt = mcasp->rxnumevt;
Shouldn't this use the same calculation that's used to set
dma_data->maxburst? Also we should add this to the dmaengine PCM driver,
since there will most likely be more DMA controllers with this restriction,
doesn't necessarily need to be done in this patch series though.
> +
> + if (afifo_numevt > 1) {
> + snd_pcm_hw_constraint_step(substream->runtime, 0,
> + SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
> + afifo_numevt);
> +
> + snd_pcm_hw_constraint_step(substream->runtime, 0,
> + SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
> + afifo_numevt);
> + }
> +
> return 0;
> }
>
>
next prev parent reply other threads:[~2014-03-16 11:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-14 14:42 [PATCH v2 0/4] ASoC: davinci: edma dmaengine PCM and mcasp preparation Peter Ujfalusi
2014-03-14 14:42 ` [PATCH v2 1/4] ASoC: davinci: Add edma dmaengine platform driver Peter Ujfalusi
2014-03-16 10:54 ` Lars-Peter Clausen
2014-03-17 16:20 ` Mark Brown
2014-03-14 14:42 ` [PATCH v2 2/4] ASoC: davinci-mcasp: Provide correct filter_data for dmaengine for non-DT boot Peter Ujfalusi
2014-03-17 16:21 ` Mark Brown
2014-03-14 14:42 ` [PATCH v2 3/4] ASoC: davinci-mcasp: Constraint on the period and buffer size based on FIFO usage Peter Ujfalusi
2014-03-16 11:18 ` Lars-Peter Clausen [this message]
2014-03-17 13:28 ` Peter Ujfalusi
2014-03-17 16:52 ` Mark Brown
2014-03-18 12:35 ` Peter Ujfalusi
2014-03-18 12:42 ` Mark Brown
2014-03-14 14:42 ` [PATCH v2 4/4] ASoC: davinci-mcasp: Assign the dma_data earlier in dai_probe callback Peter Ujfalusi
2014-03-17 16:44 ` Mark Brown
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