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

[Mike Travis]

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.

> 
>>
>> Signed-off-by: Mike Travis <travis at sgi.com>
>> Reviewed-by: Mike Habeck <habeck at 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)
>>
> 
> 
>