From: Russell King <rmk+alsa@arm.linux.org.uk>
To: Jaroslav Kysela <perex@suse.cz>
Cc: "Gupta, Kshitij" <kshitij@ti.com>, alsa-devel@lists.sourceforge.net
Subject: Re: buffer producer/consumer sync
Date: Wed, 31 Mar 2004 09:53:06 +0100 [thread overview]
Message-ID: <20040331095306.A32258@flint.arm.linux.org.uk> (raw)
In-Reply-To: <Pine.LNX.4.58.0403311027290.1950@pnote.perex-int.cz>; from perex@suse.cz on Wed, Mar 31, 2004 at 10:29:06AM +0200
On Wed, Mar 31, 2004 at 10:29:06AM +0200, Jaroslav Kysela wrote:
> On Wed, 31 Mar 2004, Russell King wrote:
> > Keeping the existing ->nopage will not work - there is no way to get to
> > a struct page on ARM given the information available to the ALSA code.
>
> Looking to arch/arm/mm/consistent.c - vm_region_find / pfn_to_page?
No - we don't have a pfn to start with, and I'm not implementing an
interface which returns a struct page because, as was agreed on
linux-arch, such an interface is completely wrong.
The correct interface is dma_mmap_coherent().
I'm actually tempted to provide dma_mmap_coherent() and just let
everyone else whinge and moan that the API doesn't meet their
expectations.
BTW, ARM also needs the mark_pages and unmark_pages functions commented
out since they're also trying to use virt_to_page() on virtual addresses
that this function is not supposed to - except for the ISA DMA case
(and yes, we have ISA DMA-based sound cards as well.)
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/
2.6 Serial core
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next prev parent reply other threads:[~2004-03-31 8:53 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-31 5:02 buffer producer/consumer sync Gupta, Kshitij
2004-03-31 7:31 ` Russell King
2004-03-31 7:44 ` Jaroslav Kysela
2004-03-31 7:53 ` Russell King
2004-03-31 8:10 ` Jaroslav Kysela
2004-03-31 8:11 ` Russell King
2004-03-31 8:29 ` Jaroslav Kysela
2004-03-31 8:53 ` Russell King [this message]
2004-03-31 9:07 ` Jaroslav Kysela
2004-03-31 9:10 ` Russell King
2004-03-31 9:22 ` Jaroslav Kysela
2004-03-31 9:27 ` Russell King
2004-03-31 11:31 ` James Courtier-Dutton
-- strict thread matches above, loose matches on Subject: below --
2004-03-09 11:33 Gupta, Kshitij
2004-03-09 11:46 ` Russell King
2004-03-09 10:40 Gupta, Kshitij
2004-03-09 9:51 Gupta, Kshitij
2004-03-09 9:53 ` Jaroslav Kysela
2004-03-09 10:18 ` Russell King
2004-03-09 10:23 ` Jaroslav Kysela
2004-03-09 10:43 ` Russell King
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