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SubjectRe: Next round of console patches

>> So the PCI bus addresses that the FB code finds may well contain MMIO
>> registers?

vesafb does'nt scan PCI space.

>A good portion of cards map their IO registers in the end of the memory
>aperture. Since the idea of fb is to use VESA call to create the aperture
>and then _dont use_ any registers at all (bc then we would have to know
>what is the specific card we are running) there is no way (apriori) to
>know where we have legal framebuffer space and where we have MMIO
>registers

There is. The VESA BIOS will tell you (a) how much video memory the board
has installed and (b) where the linear framebuffer starts. vesafb (well,
the real mode boot code) asks the BIOS for these values and uses this for
the framebuffer device. And for exactly this area the mtrr entry is added.

Assuming legal framebuffer space and MMIO don't overlap, this works fine.

Gerd

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powered by vim | Gerd Knorr <kraxel@cs.tu-berlin.de>
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