Date: Thu, 26 Nov 2009 18:15:54 +0000
From: Ralf Baechle <ralf@linux-mips.org>
To: Takashi Iwai <tiwai@suse.de>
Cc: wuzhangjin@gmail.com, Andreas Mohr <andi@lisas.de>,
       linux-kernel@vger.kernel.org
Subject: Re: snd_usb_audio OOPS on MIPSEL - is that the mmap issue?
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On Thu, Nov 26, 2009 at 10:09:04AM +0100, Takashi Iwai wrote:

> I guess it won't, because usb audio driver provides its own page
> callback.  It uses vmalloced buffer as the primary buffer, then
> copies to the urb transfer buffer.  So, mmap should work as long as
> the page returned from vmalloc_to_page() can be mapped.

You mean mapping a page that is mapped to the vmalloc area of the kernel
also to userland?  That's a fairly safe way to create cache aliases on
those platforms that suffer from them.

  Ralf
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