Re: K6-2, Stepping 12, MTRR in 2.2.6

Matthew Vanecek (mev0003@unt.edu)
Mon, 19 Apr 1999 09:23:30 -0500


Richard Gooch wrote:
>
> Matthew Vanecek writes:
> > Is there something special I'm supposed to do to enable MTRR with the
> > K6-2 stepping 12 processor? My understanding was that they were
> > supposed to work with stepping 8/9 and above. My further understanding
> > was that /proc/mtrr was supposed to be created automagically. Am I
> > doing something wrong, or has Linus not include the K6--2 MTRR fixes in
> > the current kernels? If not, then, when?
>
> Linus' kernels don't have MTRR support for Cyrix or AMD. Grab my MTRR
> patch from: http://www.atnf.csiro.au/~rgooch/linux/kernel-patches.html
>
> This has been submitted to Linus. I'm waiting for his comments.
>
> Regards,
>
> Richard....

Oops, last message I sent didn't go to mailing list, so...
I applied Richards patch to the 2.2.6 tree. There was only one failure,
in vesafb.c. I made the following changes to make it look like
Richard's patch:

--- vesafb.c.orig Sun Apr 18 02:26:11 1999
+++ vesafb.c Sun Apr 18 23:29:32 1999
@@ -635,10 +635,10 @@
video_cmap_len = 256;
}
request_region(0x3c0, 32, "vga+");
-#ifdef CONFIG_MTRR
- if (mtrr)
+// #ifdef CONFIG_MTRR
+// if (mtrr)
mtrr_add((unsigned long)video_base, video_size,
MTRR_TYPE_WRCOMB
, 1);
-#endif
+//#endif

strcpy(fb_info.modename, "VESA VGA");
fb_info.changevar = NULL;

I recompiled and rebooted, and voila! /proc/mtrr magically appeared! I
performed the appropriate 'echo's and went merrily on my way.

How do I test that /proc/mtrr is actually being used? Also, what is
Linux waiting for to add this code to the kernel? Does he need some
more stability testing? If so, what tests can I run to prove the code's
stability?

-- 
Matthew Vanecek
Course of Study: http://www.unt.edu/bcis
Visit my Website at http://people.unt.edu/~mev0003
For answers type: perl -e 'print
$i=pack(c5,(41*2),sqrt(7056),(unpack(c,H)-2),oct(115),10);'
*****************************************************************
For 93 million miles, there is nothing between the sun and my shadow
except me. I'm always getting in the way of something...

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