From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: "Mark A. Greer" <mgreer@animalcreek.com>,
linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Jarkko Nikula <jarkko.nikula@bitmer.com>
Subject: Re: [RFC] dmaengine: omap-dma: Allow DMA controller to prefetch data
Date: Mon, 19 Nov 2012 11:00:15 +0100 [thread overview]
Message-ID: <50AA032F.1010102@ti.com> (raw)
In-Reply-To: <20121117113159.GM3332@n2100.arm.linux.org.uk>
On 11/17/2012 12:31 PM, Russell King - ARM Linux wrote:
> On Fri, Oct 19, 2012 at 02:45:55PM +0200, Péter Ujfalusi wrote:
>> Hi,
>>
>> On 10/19/2012 01:33 AM, Russell King - ARM Linux wrote:
>>> I'm merely pointing out here that we need their feedback here before
>>> deciding if there's anything further that needs to happen.
>>
>> Thanks Russell, I'll take a look at the implication of the prefetch for audio.
>
> Péter, any news?
Sorry, I was carried away with other things...
I did some testing with and without the dma prefetch for audio (on BeagleBoard
with mplayer: -ao alsa/pulse).
When we have prefetch enabled we tend to resume after pause from a slightly
off place than when the prefetch is disabled.
I also remember that in n9 we have had some issue with the DMA prefetch.
So I would for sure enable the prefetch for non cyclic DMA.
For the cyclic I would not enable it for now. I need to dig a bit deeper in
DMA/McBSP to have better view on the issue.
I have one comment to the patch itself as well.
--
Péter
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WARNING: multiple messages have this Message-ID (diff)
From: peter.ujfalusi@ti.com (Peter Ujfalusi)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC] dmaengine: omap-dma: Allow DMA controller to prefetch data
Date: Mon, 19 Nov 2012 11:00:15 +0100 [thread overview]
Message-ID: <50AA032F.1010102@ti.com> (raw)
In-Reply-To: <20121117113159.GM3332@n2100.arm.linux.org.uk>
On 11/17/2012 12:31 PM, Russell King - ARM Linux wrote:
> On Fri, Oct 19, 2012 at 02:45:55PM +0200, P?ter Ujfalusi wrote:
>> Hi,
>>
>> On 10/19/2012 01:33 AM, Russell King - ARM Linux wrote:
>>> I'm merely pointing out here that we need their feedback here before
>>> deciding if there's anything further that needs to happen.
>>
>> Thanks Russell, I'll take a look at the implication of the prefetch for audio.
>
> P?ter, any news?
Sorry, I was carried away with other things...
I did some testing with and without the dma prefetch for audio (on BeagleBoard
with mplayer: -ao alsa/pulse).
When we have prefetch enabled we tend to resume after pause from a slightly
off place than when the prefetch is disabled.
I also remember that in n9 we have had some issue with the DMA prefetch.
So I would for sure enable the prefetch for non cyclic DMA.
For the cyclic I would not enable it for now. I need to dig a bit deeper in
DMA/McBSP to have better view on the issue.
I have one comment to the patch itself as well.
--
P?ter
next prev parent reply other threads:[~2012-11-19 10:01 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-18 22:20 [RFC] dmaengine: omap-dma: Allow DMA controller to prefetch data Mark A. Greer
2012-10-18 22:20 ` Mark A. Greer
2012-10-18 22:46 ` Mark A. Greer
2012-10-18 22:46 ` Mark A. Greer
2012-10-18 22:55 ` Russell King - ARM Linux
2012-10-18 22:55 ` Russell King - ARM Linux
2012-10-18 23:24 ` Mark A. Greer
2012-10-18 23:24 ` Mark A. Greer
2012-10-18 23:33 ` Russell King - ARM Linux
2012-10-18 23:33 ` Russell King - ARM Linux
2012-10-18 23:50 ` Mark A. Greer
2012-10-18 23:50 ` Mark A. Greer
2012-10-19 12:45 ` Péter Ujfalusi
2012-10-19 12:45 ` Péter Ujfalusi
2012-11-05 22:06 ` Mark A. Greer
2012-11-05 22:06 ` Mark A. Greer
2012-11-16 22:39 ` Mark A. Greer
2012-11-16 22:39 ` Mark A. Greer
2012-11-17 11:31 ` Russell King - ARM Linux
2012-11-17 11:31 ` Russell King - ARM Linux
2012-11-19 10:00 ` Peter Ujfalusi [this message]
2012-11-19 10:00 ` Peter Ujfalusi
2012-11-19 12:16 ` Russell King - ARM Linux
2012-11-19 12:16 ` Russell King - ARM Linux
2012-11-19 10:01 ` Peter Ujfalusi
2012-11-19 10:01 ` Peter Ujfalusi
2012-11-19 16:19 ` Mark A. Greer
2012-11-19 16:19 ` Mark A. Greer
2012-11-19 16:49 ` Mark A. Greer
2012-11-19 16:49 ` Mark A. Greer
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