Re: 4MB pages and framebuffer access, x11perf results, 2.1.125

MOLNAR Ingo (mingo@chiara.csoma.elte.hu)
Thu, 29 Oct 1998 01:54:55 +0100 (CET)


On Thu, 29 Oct 1998, Andrea Arcangeli wrote:

> >+ if (off == 0xfc000000) {
> >+ addr = 0x44000000;
> >+ len = 0x00400000;
> >+ flags |= VM_LOCKED;
> >+ }
> >+

> Why you need this? Shound' t X that should set these values at first?

because _my_ card has only a 2MB phsysical framebuffer ;) I wanted the
trick to work even without the direct cooperation of X.

VM_LOCKED is needed to keep the kernel from trying to dereference *pmd in
swap_out_vma(). (this problem is solved properly by pmd_only())

another tough question is, should we allow the mapping of 4M real physical
memory, and how can we get this in a sane way.

-- mingo

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