From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Takashi Iwai <tiwai@suse.de>
Cc: linux-mips@linux-mips.org, alsa-devel@alsa-project.org,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Becky Bruce <beckyb@kernel.crashing.org>,
Wu Zhangjin <wuzhangjin@gmail.com>,
Ralf Baechle <ralf@linux-mips.org>, Andreas Mohr <andi@lisas.de>,
Kumar Gala <galak@gate.crashing.org>
Subject: Re: [PATCH 0/5] PCM mmap (temporary) fixes for non-coherent architectures
Date: Fri, 15 Jan 2010 17:50:49 +1100 [thread overview]
Message-ID: <1263538249.724.405.camel@pasglop> (raw)
In-Reply-To: <s5hvdf3lvfi.wl%tiwai@suse.de>
On Fri, 2010-01-15 at 07:43 +0100, Takashi Iwai wrote:
>
> > It -might- be worth looking at adding code to the USB stack to
> propagate
> > the parent device dma_ops down to USB devices... hard to tell.
>
> Or we may simply need to drop the mmap support on such
> architectures...
Nah, that would suck since that includes x86 nowadays :-)
I think you probably need to separate the struct device * used for DMA
(it could be default be the same as the "main" struct device tho or it
could default to NULL which means no mmap support).
USB could (if not already) provide an accessor to obtain the HC's struct
device for such mappings. We'll have to discuss that with Alan Stern I
suppose.
The USB Audio or similar drivers could then use that accessors to fill
up Alsa's dma_device field to replace the "default".
Cheers,
Ben.
next prev parent reply other threads:[~2010-01-15 6:51 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-26 15:13 [PATCH 0/5] PCM mmap (temporary) fixes for non-coherent architectures Takashi Iwai
2009-11-26 15:13 ` [PATCH 1/5] ALSA: pcm - Use dma_mmap_coherent() if available Takashi Iwai
2009-11-26 15:13 ` [PATCH 2/5] ALSA: pcm - define snd_pcm_default_page_ops() Takashi Iwai
2009-11-26 15:13 ` [PATCH 3/5] ALSA: pcm - fix page conversion on non-coherent MIPS arch Takashi Iwai
2009-11-26 15:13 ` [PATCH 4/5] ALSA: pcm - fix page conversion on non-coherent PPC arch Takashi Iwai
2009-11-26 15:13 ` [PATCH 5/5] ALSA: Remove old DMA-mmap code from arm/devdma.c Takashi Iwai
2009-11-26 16:56 ` [PATCH 4/5] ALSA: pcm - fix page conversion on non-coherent PPC arch Takashi Iwai
2009-11-26 21:14 ` Benjamin Herrenschmidt
2009-11-26 20:51 ` Benjamin Herrenschmidt
2009-11-27 9:18 ` Takashi Iwai
2009-11-27 3:52 ` [PATCH 3/5] ALSA: pcm - fix page conversion on non-coherent MIPS arch Wu Zhangjin
2009-11-27 9:26 ` Takashi Iwai
2009-11-27 8:46 ` Ralf Baechle
2009-11-27 9:20 ` Takashi Iwai
2010-01-01 19:31 ` [PATCH 0/5] PCM mmap (temporary) fixes for non-coherent architectures Andreas Mohr
2010-01-12 7:02 ` Takashi Iwai
2010-01-13 9:07 ` Takashi Iwai
2010-01-14 7:46 ` Andreas Mohr
2010-01-14 7:54 ` Takashi Iwai
2010-01-15 3:28 ` Benjamin Herrenschmidt
2010-01-15 6:43 ` Takashi Iwai
2010-01-15 6:50 ` Benjamin Herrenschmidt [this message]
2010-01-15 7:32 ` Takashi Iwai
2010-01-13 9:28 ` Andreas Mohr
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