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Re: O2 RM7000 Issues

To: Sagar Borikar <Sagar_Borikar@pmc-sierra.com>
Subject: Re: O2 RM7000 Issues
From: Ralf Baechle <ralf@linux-mips.org>
Date: Fri, 21 Sep 2007 14:47:53 +0100
Cc: Steve Graham <stgraham2000@yahoo.com>, linux-mips@linux-mips.org
In-reply-to: <340C71CD25A7EB49BFA81AE8C839266757076E@BBY1EXM10.pmc_nt.nt.pmc-sierra.bc.ca>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <340C71CD25A7EB49BFA81AE8C839266757076E@BBY1EXM10.pmc_nt.nt.pmc-sierra.bc.ca>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.5.14 (2007-02-12)
On Thu, Sep 20, 2007 at 11:27:18PM -0700, Sagar Borikar wrote:

> rm7k_wait_irqoff patch doesn't seem to improve the things for illegal 
> instructions for E9k core.
> But many customers have reported that they do get illegal instruction when 
> ICACHE_REFILLS_WORKAROUND_WAR is not enabled.

This is due to a very unfortunate design issue in the RM7000 / RM9000.  So
it wasn't done by accident but with full intention but I call it a bug
anyway.  So this also means all revs of these cores are affected and if
the issue is not being hit for a particular workload and where
ICACHE_REFILLS_WORKAROUND_WAR is disabled then that that's by coincidence
not engineering.

  Ralf

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