From: Jussi Kivilinna <jussi.kivilinna@iki.fi>
To: "Jörn Engel" <joern@logfs.org>
Cc: David Woodhouse <dwmw2@infradead.org>,
linux-usb@vger.kernel.org, linux-mtd@lists.infradead.org
Subject: Re: [PATCH] alauda: do not use stack for URB transfer_buffers
Date: Wed, 07 Aug 2013 08:50:53 +0300 [thread overview]
Message-ID: <5201E03D.30306@iki.fi> (raw)
In-Reply-To: <20130806164913.GD10535@logfs.org>
On 06.08.2013 19:49, Jörn Engel wrote:
> On Tue, 6 August 2013 15:03:29 +0300, Jussi Kivilinna wrote:
>>
>> Patch fixes alauda not to use stack as URB transfer_buffer. URB buffers need to
>> be DMA-able, which stack is not.
>>
>> Patch is only compile tested.
>
> I have tested the driver back when I wrote it. Not sure why it worked
> then, maybe the chip in my notebook back then didn't care about
> alignment or I just got lucky with the memory allocations.
You might not see problems with your hardware/architecture.
"Documentation/DMA-API-HOWTO.txt" discusses about "What memory is DMA'able?".
>
> My old test hardware was likely thrown out in the last move, about two
> years back. Performance sucked anyway, 400kB/s was the limit. Maybe
> we should just remove the driver and not spend any more time on it?
>
> Jörn
>
> --
> Victory in war is not repetitious.
> -- Sun Tzu
>
next prev parent reply other threads:[~2013-08-07 5:51 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 12:03 [PATCH] alauda: do not use stack for URB transfer_buffers Jussi Kivilinna
2013-08-06 16:49 ` Jörn Engel
2013-08-07 5:50 ` Jussi Kivilinna [this message]
2013-08-07 15:16 ` Jörn Engel
2013-08-21 7:30 ` Brian Norris
2013-08-21 7:59 ` Bjørn Mork
2013-08-21 8:41 ` Brian Norris
2013-08-21 9:59 ` Jussi Kivilinna
2013-08-21 20:00 ` Brian Norris
2013-08-21 19:06 ` Jörn Engel
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