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Re: [PATCH] JAZZ: disable PIT; cleanup R4030 clockevent

To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Subject: Re: [PATCH] JAZZ: disable PIT; cleanup R4030 clockevent
From: Ralf Baechle <ralf@linux-mips.org>
Date: Thu, 1 Nov 2007 16:02:10 +0000
Cc: linux-mips@linux-mips.org
In-reply-to: <20071101150741.GA8570@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20071101125236.GA16577@alpha.franken.de> <20071101150741.GA8570@linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.5.14 (2007-02-12)
On Thu, Nov 01, 2007 at 03:07:41PM +0000, Ralf Baechle wrote:

> On Thu, Nov 01, 2007 at 01:52:36PM +0100, Thomas Bogendoerfer wrote:
> 
> > PIT doesn't work, disable it completly
> 
> I think this is the explanation:
> 
> include/asm-mips/mach-jazz/timex.h:#define CLOCK_TICK_RATE              100
> 
> while the PIT code actually expects 1193182.
> 
> Turns out that due to a recent Qemu bug which made the probe for the cp0
> compare interrupt fail the Malta code did fall back from the compare timer
> to the i8253 PIT for the clockevent device.  Works perfectly well.

So I just fixed the MIPS part of the CLOCK_TICK_RATE mess which is really
all over the kernel.  I hope this should bring the i2853 to life for you.
Could you test this?  It's pretty much the only hope for Jazz to go tickless
so we should try to get it to work.  Unfortunately there is a locking issue
lurking there as well so I need some feedback if you can get it to work.

  Ralf

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