Re: [PATCH] agp/intel: Fix dma mask for Sandybridge

[Zhenyu Wang]

On 2010.08.23 08:02:42 +0200, Takashi Iwai wrote:
> 
> Also, I don't understand the logic of 40bit addr calculation:
> 
> > static unsigned long intel_gen6_mask_memory(struct agp_bridge_data *bridge,
> >                                             dma_addr_t addr, int type)
> > {
> >         /* Shift high bits down */
> >        addr |= (addr >> 28) & 0xff;
> 
> Isn't it 0xff0?
> 

No. This depends on hw 32bit PTE format for sandybridge.

bit 31			 bit 11			 bit 4			bit 0
   |<-physical addr 31:12->|<-physical addr 39:32->|<-cache ctl 3:1->|valid|

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