Messages in this thread | | | From | Jesse Barnes <> | Subject | Re: 2.6.26-rc1 regression: ISA DMA broken (bisected) | Date | Fri, 9 May 2008 10:20:22 -0700 |
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On Friday, May 09, 2008 1:58 am Ingo Molnar wrote: > * Ingo Molnar <mingo@elte.hu> wrote: > > good catch! Queued it up for testing. Jesse, do you concur? > > here's the patch below, tidied up.
Yeah, that looks like a clear problem. :)
> -------------------------------> > Subject: x86/pci: fix broken ISA DMA > From: Takashi Iwai <tiwai@suse.de> > Date: Fri, 09 May 2008 08:06:55 +0200 > > 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.
Patch looks good, applied to my 'for-linus' tree.
Thanks, Jesse
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