Subject: Re: PXA250 Xscale and page tables
To: Jason R Thorpe <>
From: Richard Earnshaw <>
List: tech-kern
Date: 03/13/2003 22:54:45
> On Mon, Feb 03, 2003 at 09:32:29AM -0700, Colin Cook wrote:
>  > Thanks for the education, I think I get the picture. However, I am still
>  > lost as to the proper fix. Can you guys think of why the pages are being
>  > mapped to more than one place? I am using 1.6 now and it still happens.
>  > There is no hard disk on this system, everything is read directly from a RAM
>  > drive which was decompressed from flash on boot. It's a very basic setup. Is
>  > there a debug command I can use to find out where the other pages are mapped
>  > to and who/why allocated them?
> FWIW...
> Steve Woodford did some legwork, and was able to reproduce the bug.  The
> test case relied on using a disk, which may be why some of us didn't see
> it; many developers use NFS root for their ARM development systems.
> In any case, once Steve was able to describe the scenario that his test
> case revealed, I was able to fix the problem rather quickly.
> Please back out any local patches you have already made to work around
> the problem, and instead apply the following patch, and please tell me
> if it fixes the problem for you or if the problem still persists.  This
> patch *did* fix Steve's test case.

This (or something else recently) has fixed the slow "just-compiled 
dhrystone" problem I mentioned to you before Xmas.