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Date: Sat, 13 Dec 2003 18:07:51 +0100
From: Ralf Baechle <ralf@linux-mips.org>
To: Peter Horton <phorton@bitbox.co.uk>
Cc: linux-mips@linux-mips.org
Subject: Re: Kernel 2.4.23 on Cobalt Qube2 - area of problem
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On Fri, Dec 12, 2003 at 10:45:08AM +0000, Peter Horton wrote:

> More info on the random segmentation faults and data corruption on my Qube2.
> 
> 2.4.21 from CVS is the first kernel to exhibit the problem. I tracked it 
> down to the cache handling changes that went in between 2.4.20 and 2.4.21.
> 
> By (not very scientifically) removing flush_dcache_page() and 
> re-instating flush_page_to_ram() I managed to get the 2.4.21 kernel 
> stable (see attached patch). Applying a similiar patch to 2.4.23 (CVS 
> HEAD) allows me to run 2.4.23 too.
> 
> I don't know how to track the problem any further - the kernel's cache 
> handling is a bit out of my league.
> 
> Anyone got a clue stick they can point me in the right direction with ?

Can you put a printk into c-r4k.c and print the value of the
shm_align_mask variable?  I want to make sure it's got a sane value on
your box.  Also the first few lines of your bootup messages with the
processor and cache stuff would be useful.

  Ralf