From: Mark Brown <broonie@kernel.org>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Takashi Iwai <tiwai@suse.de>,
lgirdwood@gmail.com, tiwai@suse.com, perex@perex.cz,
lars@metafoo.de, alsa-devel@alsa-project.org, vkoul@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ASoC: dmaengine_pcm: Consider DMA cache caused delay in pointer callback
Date: Mon, 10 Feb 2020 14:37:17 +0000 [thread overview]
Message-ID: <20200210143717.GO7685@sirena.org.uk> (raw)
In-Reply-To: <15c7df10-cf9f-109c-3cbf-e73af7f4f66a@ti.com>
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On Mon, Feb 10, 2020 at 04:28:44PM +0200, Peter Ujfalusi wrote:
> On 10/02/2020 16.21, Takashi Iwai wrote:
> >> delay += codec_delay;
> >>
> >> - runtime->delay = delay;
> >> + runtime->delay += delay;
> > Is it correct?
> > delay already takes runtime->delay as its basis, so it'll result in a
> > double.
> The delay here is coming from the DAI and the codec.
> The runtime->delay hold the PCM (DMA) caused delay.
I think Takashi's point here (and a query I have) is that we end up with
delay = runtime->delay;
delay += stuff;
runtime->delay += delay;
which is equivalent to
runtime->delay = (runtime->delay * 2) + stuff;
and that's a bit surprising.
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next prev parent reply other threads:[~2020-02-10 14:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-10 14:04 Peter Ujfalusi
2020-02-10 14:21 ` Takashi Iwai
2020-02-10 14:28 ` Peter Ujfalusi
2020-02-10 14:37 ` Mark Brown [this message]
2020-02-10 14:59 ` Peter Ujfalusi
2020-02-10 14:38 ` Takashi Iwai
2020-02-10 15:01 ` Peter Ujfalusi
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