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SubjectRe: OpenGL-based framebuffer concepts
Date
On Wednesday 24 May 2006 22:08, Matthew Garrett wrote:
> On Tue, May 23, 2006 at 07:38:40PM -0400, Jon Smirl wrote:
> > 2) The ROM support in the kernel knows about the shadow RAM copy at
> > C000::0. When you request the ROM from a laptop video system it
> > returns a map to the shadow RAM copy, not to a physical ROM. You need
> > access to the shadow RAM copy to get to things the BIOS left there
> > when it ran.
>
> My experience is that, on some laptops, the code at c000:0003 may jump
> into some other address block that isn't necessarily shadowed. There's
> no reason to assume that POSTing an ancilliary ROM will work after the
> system has left the BIOS. Further, my laptop doesn't appear to have a
> rom entry in sysfs, which makes getting at stuff that way rather more
> awkward...

As has been previously stated, the kernel should have already setup the
primary video card by that point. EDID information can be used to get
information about valid modes. I don't know of a single laptop that has
multiple video cards in it. If you do, please enlighten me.

DRH
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