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

From: Takashi Iwai
Date: Mon Aug 23 2010 - 02:03:06 EST


At Mon, 23 Aug 2010 13:43:03 +0800,
Zhenyu Wang wrote:
>
> On 2010.08.23 07:29:29 +0200, Takashi Iwai wrote:
> > > Sandybridge can do 40-bit dma mask. This has been fixed upstream now.
> >
> > Could you point where is the upstream GIT tree and the corresponding
> > commit id?
> >
>
> Linus's tree:
>
> commit 877fdacf8291d7627f339885b5ae52c2f6061734
> Author: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
> Date: Thu Aug 19 09:46:13 2010 +0800
>
> agp/intel: set 40-bit dma mask on Sandybridge
>
> Signed-off-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>

Thanks.

But, isn't it better to add .dma_mask field to struct
agp_bridge_driver?

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?


Takashi
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