Re: [PATCH 2/2] x86: add early quirk for reserving Intel graphicsstolen memory v3

From: H. Peter Anvin
Date: Fri Jul 26 2013 - 12:59:32 EST


On 07/25/2013 09:37 AM, Jesse Barnes wrote:
> Systems with Intel graphics controllers set aside memory exclusively for
> + /*
> + * Almost universally we can find the Graphics Base of Stolen Memory
> + * at offset 0x5c in the igfx configuration space. On a few (desktop)
> + * machines this is also mirrored in the bridge device at different
> + * locations, or in the MCHBAR.
> + */

This comment makes me nervous. It isn't clear to me if it is saying:

- All igfx devices has the graphics base at 0x5c, a few have it in
other places, too (which doesn't matter, we can use 0x5c anyway), or
- Most igfx devices have the graphics base at 0x5c, some don't, and we
hope and pray we're not on one of those systems because we're not
checking.

I assume it is the former, but it really needs to be phrased better.

-hpa


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