From: Lars-Peter Clausen <lars@metafoo.de>
To: Tushar Behera <tushar.behera@linaro.org>
Cc: Jassi Brar <jassisinghbrar@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dmaengine@vger.kernel.org, Vinod Koul <vinod.koul@intel.com>,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH] dma: pl330: Add support for DMA_PAUSE command
Date: Wed, 14 May 2014 14:24:29 +0200 [thread overview]
Message-ID: <5373607D.2000200@metafoo.de> (raw)
In-Reply-To: <CAHbNUh0fVND_oGLXWzsyKzbmJc_=FqhZTAnVHE4GGZ5aaJQbEg@mail.gmail.com>
On 05/14/2014 02:07 PM, Tushar Behera wrote:
> On 14 May 2014 17:29, Jassi Brar <jassisinghbrar@gmail.com> wrote:
>> On Wed, May 14, 2014 at 8:53 AM, Tushar Behera <tushar.behera@linaro.org> wrote:
>>> While playing back audio, pmc_dmaengine requests the DMA channel to
>>> stop DMA transmission through DMA_PAUSE command.
>>>
>>> Currently PL330 driver doesn't support DMA pause command, leaving
>>> the DMA state inconsistent when the system resumes. Instead, it would
>>> be better to terminate the DMA transfer during suspend and restart
>>> again during resume.
>>>
>>> Tested with audio playback across a suspend-resume cycle.
>>>
>> What is pmc_dmaengine? How does DMA_PAUSE help, when there is no DMA_RESUME?
>>
>
> Sorry, it is a typo.
>
> sound/core/pcm_dmaengine.c:snd_dmaengine_pcm_trigger() -->
> dmaengine_pause() is called during system suspend.
It is only called if the DMA driver has support for pausing and resuming DMA
transfers. Or at least that is the intention.
- Lars
next prev parent reply other threads:[~2014-05-14 12:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-14 3:23 [PATCH] dma: pl330: Add support for DMA_PAUSE command Tushar Behera
2014-05-14 11:59 ` Jassi Brar
2014-05-14 12:07 ` Tushar Behera
2014-05-14 12:24 ` Lars-Peter Clausen [this message]
2014-05-15 12:01 ` Tushar Behera
2014-05-15 19:21 ` Lars-Peter Clausen
2014-05-15 19:21 ` Lars-Peter Clausen
2014-05-16 5:49 ` Takashi Iwai
2014-05-16 5:49 ` Takashi Iwai
2014-05-16 10:51 ` Lars-Peter Clausen
2014-05-16 10:51 ` [alsa-devel] " Lars-Peter Clausen
2014-05-19 8:37 ` Takashi Iwai
2014-05-19 8:43 ` Lars-Peter Clausen
2014-05-19 3:10 ` Tushar Behera
2014-05-19 5:57 ` Lars-Peter Clausen
2014-05-14 13:16 ` Jassi Brar
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