[PATCH 4/4] sounds/hda/radeon: Disable 64-bit DMA on radeon

[Takashi Iwai]

At Wed, 01 Oct 2014 12:09:53 +1000,
Benjamin Herrenschmidt wrote:
> 
> The chipset has a limitation in the number of address bits it
> can generate. The graphics portion uses a specific mask of
> 40 or 48 bits depending on the generation. For audio, it's a bit
> less of an issue, so just mark them as no-64bit for now.
> 
> Without this, it crashes on POWER machines which can use high bits
> in the DMA address to distinguish between DMA windows. 
> 
> Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> CC: <stable at vger.kernel.org>
> ---
>  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 3e6d22d..2b679d5 100644
> --- a/sound/pci/hda/hda_intel.c
> +++ b/sound/pci/hda/hda_intel.c
> @@ -297,7 +297,7 @@ enum {
>  /* quirks for ATI/AMD HDMI */
>  #define AZX_DCAPS_PRESET_ATI_HDMI \
>  	(AZX_DCAPS_NO_TCSEL | AZX_DCAPS_SYNC_WRITE | AZX_DCAPS_POSFIX_LPIB|\
> -	 AZX_DCAPS_NO_MSI64)
> +	 AZX_DCAPS_NO_MSI64 | AZX_DCAPS_NO_64BIT)

The only concern is that this will disable 64bit DMA also on x86 where
it has been working fine.  Can we add an ifdef CONFIG_PPC for this?


Takashi