From: Takashi Iwai <tiwai@suse.de>
Date: Fri, 9 May 2008 06:06:55 +0000 (+0200)
Subject: x86/PCI: fix broken ISA DMA
X-Git-Tag: v2.6.26-rc3~70^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a367f3a9dbf2e7ffcee4702203479809236ee6e;p=pandora-kernel.git

x86/PCI: fix broken ISA DMA

Rene Herman reported:

> commit 8779f2fc3b84ebb6c5181fb13d702e9944c16069
>
> "x86: don't try to allocate from DMA zone at first"
>
> breaks all of ISA DMA. Or all of ALSA ISA DMA at least. All
> ISA soundcards are silent following that commit -- no error
> messages, everything appears fine, just silence.

That patch is buggy. We had an implicit assumption that
dev = NULL for ISA devices that require 24bit DMA.

The recent work on x86 dma_alloc_coherent() breaks the ISA DMA buffer
allocation, which is represented by "dev = NULL" and requires 24bit
DMA implicitly.

Bisected-by: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---

Reading git-diff-tree failed