Re: Next round of console patches
Tom Eastep (tom.easep@tandem.com)
Sat, 29 Aug 1998 19:20:09 -0700
Richard Gooch wrote:
> OK, that would make sense if the write-combining is fouling up MMIO
> register access. Can you please patch your kernel where it calls
> mtrr_add() and add another call to mtrr_add() so that you set up a
> small uncacheable region either at the beginning or the end of the
> framebuffer?
> With luck that will fix it. If it does, start trimming the uncacheable
> region down in size until it fails again. That will tell you the
> minimum size of the register region. If you're unsure of how big a
> region to start with (say 4 kBytes still fails), make the entire
> framebuffer uncacheable and step down in factors of two.
Ok -- I patched vesafb.c as follows:
mtrr_add((unsigned long)video_base, video_size, MTRR_TYPE_WRCOMB, 1);
+ mtrr_add((unsigned long)video_base, video_size, MTRR_TYPE_UNCACHABLE,
1);
I still got the lockup.
-Tom
--
Tom Eastep Tandem Division of COMPAQ
tom.eastep@tandem.com
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