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SubjectRe: [PATCH]: x86_64, audio: Fix system panic when DMA > 40 bits
On 05/02/2013 08:36 AM, Mike Travis wrote:
>
>
> On 5/1/2013 11:20 PM, 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?
>
> The dma_mask can be read from the gpu device's pci entry. I know it's
> a stretch to try to link to that but past history has shown that it
> ranges from 36 to 40 bits.

Ok, so the below patch is some kind of workaround, as we don't currently
take the dma_mask into account correctly? Or put in another way, would
it be possible/better to actually read the dma_mask and use that instead
of just clamping at 32 bit?

>
>>
>>>
>>> Signed-off-by: Mike Travis <travis@sgi.com>
>>> Reviewed-by: Mike Habeck <habeck@sgi.com>
>>> ---
>>> sound/pci/hda/hda_intel.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
>>> index bcd40ee..45eb165 100644
>>> --- a/sound/pci/hda/hda_intel.c
>>> +++ b/sound/pci/hda/hda_intel.c
>>> @@ -615,7 +615,7 @@ enum {
>>> /* quirks for Nvidia */
>>> #define AZX_DCAPS_PRESET_NVIDIA \
>>> (AZX_DCAPS_NVIDIA_SNOOP | AZX_DCAPS_RIRB_DELAY |
>>> AZX_DCAPS_NO_MSI |\
>>> - AZX_DCAPS_ALIGN_BUFSIZE)
>>> + AZX_DCAPS_ALIGN_BUFSIZE | AZX_DCAPS_NO_64BIT)
>>>
>>> #define AZX_DCAPS_PRESET_CTHDA \
>>> (AZX_DCAPS_NO_MSI | AZX_DCAPS_POSFIX_LPIB |
>>> AZX_DCAPS_4K_BDLE_BOUNDARY)
>>>
>>
>>
>>
>



--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic


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