linux-mips
[Top] [All Lists]

Re: About MIPS specific dma_mmap_coherent()

To: Takashi Iwai <tiwai@suse.de>
Subject: Re: About MIPS specific dma_mmap_coherent()
From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 11 May 2010 19:48:44 +0100
Cc: wuzhangjin@gmail.com, linux-mips <linux-mips@linux-mips.org>
In-reply-to: <s5h633uxcje.wl%tiwai@suse.de>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1271134735.25797.35.camel@falcon> <s5hmxx7z4a7.wl%tiwai@suse.de> <1271218889.25872.27.camel@falcon> <s5hzl164kay.wl%tiwai@suse.de> <1271235619.25872.148.camel@falcon> <s5h633uxcje.wl%tiwai@suse.de>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.5.20 (2009-08-17)
On Wed, Apr 14, 2010 at 05:46:13PM +0200, Takashi Iwai wrote:

> But, I remember vaguely that calling pgprot_noncached()
> unconditionally is dangerous.  It should be checked somehow, e.g. via
> platform_device_is_coherent().  And, this found only in
> dma-coherence.h, and adding it to pcm_native.c would become messy like
> below...
> 
> So, it'd be really better to add dma_mmap_coherent(), indeed.

We agreed that this was only meant as a stop gap meassure.  As such I do
agree with either of

  http://patchwork.linux-mips.org/patch/1117/
  http://patchwork.linux-mips.org/patch/1118/

Wu has tested the 1117 patch so that might make it preferable especially
for 2.6.34 if we should go for that.

  Ralf

<Prev in Thread] Current Thread [Next in Thread>