From: Oliver Neukum <oliver@neukum.org>
To: Clemens Ladisch <clemens@ladisch.de>
Subject: Re: USB mass storage and ARM cache coherency
Date: Tue, 2 Feb 2010 15:52:19 +0100
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Cc: Andreas Mohr <andi@lisas.de>, Catalin Marinas <catalin.marinas@arm.com>,
       Matthew Dharm <mdharm-kernel@one-eyed-alien.net>,
       Sergei Shtylyov <sshtylyov@ru.mvista.com>,
       Ming Lei <tom.leiming@gmail.com>, linux-usb@vger.kernel.org,
       "linux-kernel" <linux-kernel@vger.kernel.org>,
       Sebastian Siewior <bigeasy@linutronix.de>, Greg KH <greg@kroah.com>
References: <20100129185434.GH19501@one-eyed-alien.net> <20100202121116.GA24926@rhlx01.hs-esslingen.de> <4B6839E9.1040407@ladisch.de>
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Am Dienstag, 2. Februar 2010 15:42:49 schrieb Clemens Ladisch:
> > Or... usb-audio? I should have verified that it is using bulk endpoints
> > (and thus the patch applies to my case).
> > usb-audio probably uses isochronous transfers, thus that would be
> > an obvious reason why the patch didn't work for me.
> 
> snd-usb-audio indeed uses isochronous transfers, but those buffers are
> never mapped into user space.  The intermediate vmalloc()ed buffer is,
> however, and there was a bugfix for this recently.  Do you have these
> patches in your tree?

Now that I think about it, several video drivers do map it to user space.

	Regards
		Oliver
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