From: Fabio Estevam <festevam@gmail.com>
To: Caleb Crome <ccrome@gmail.com>
Cc: Timur Tabi <timur@tabi.org>,
Nicolin Chen <nicoleotsuka@gmail.com>,
Xiubo Li <Xiubo.Lee@gmail.com>,
Fabio Estevam <fabio.estevam@nxp.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>,
"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Arnaud Mouiche <arnaud.mouiche@invoxia.com>,
Caleb Crome <caleb@crome.org>
Subject: Re: [alsa-devel] [PATCH] fsl_ssi: set fifo watermark to more reliable value
Date: Tue, 3 Jan 2017 19:08:53 -0200 [thread overview]
Message-ID: <CAOMZO5AS7TPu1PmdNUZuSEJQO2C7L+7Kn2wpetoxHCzwHiyokg@mail.gmail.com> (raw)
In-Reply-To: <1483467777-8651-1-git-send-email-caleb@signalessence.com>
On Tue, Jan 3, 2017 at 4:22 PM, Caleb Crome <ccrome@gmail.com> wrote:
> From: Caleb Crome <caleb@crome.org>
>
> The fsl_ssi fifo watermark is by default set to 2 free spaces (i.e.
> activate DMA on FIFO when only 2 spaces are left.) This means the
> DMA must service the fifo within 2 audio samples, which is just not
> enough time for many use cases with high data rate. In many
> configurations the audio channel slips (causing l/r swap in stereo
> configurations, or channel slipping in multi-channel configurations).
>
> This patch gives more breathing room and allows the SSI to operate
> reliably by changing the fifio refill watermark to 8.
>
> There is no change in behavior for older chips (with an 8-deep fifo).
> Only the newer chips with a 15-deep fifo get the new behavior. I
> suspect a new fifo depth setting could be optimized on the older
> chips too, but I have not tested.
>
> Signed-off-by: Caleb Crome <caleb@crome.org>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
next prev parent reply other threads:[~2017-01-03 21:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-03 18:22 [PATCH] fsl_ssi: set fifo watermark to more reliable value Caleb Crome
2017-01-03 21:08 ` Fabio Estevam [this message]
2017-01-04 18:27 ` Mark Brown
2017-01-04 18:31 ` ccrome
2017-01-04 18:31 ` ccrome
2017-01-04 18:35 ` Mark Brown
2017-01-04 18:35 ` Mark Brown
2017-01-04 18:37 ` Applied "ASoC: fsl_ssi: set fifo watermark to more reliable value" to the asoc tree Mark Brown
2017-01-04 18:37 ` Mark Brown
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