[alsa-devel] [PATCH]: x86_64, audio: Fix system panic when DMA > 40 bits

Stephen Warren swarren at wwwdotorg.org
Thu May 2 20:20:24 CEST 2013

On 05/02/2013 12:20 AM, David Henningsson wrote:
> On 05/01/2013 09:04 PM, Mike Travis wrote:
>> The audio driver mistakenly allows 64 bit addresses to be created for
>> the audio driver on Nvidia GPUs.  Unfortunately, the hardware normally
>> only supports up to 40 bits of DMA.  This can cause system panics as
>> well as misdirected data when the address is > 40 bits as the upper
>> part the address is truncated.
> Thanks for this patch. Stephen Warren, is this something you can
> confirm/deny, and do you know what range of hardware this actually
> applies to?

It's certainly plausible that the GPU's internal physical addresses are
less than a full 64-bits, and this probably affects PCI accesses too.

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