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Re: Timer Interrupt

To: Linux MIPS <linux-mips@linux-mips.org>
Subject: Re: Timer Interrupt
From: Bharathi Subramanian <sbharathi@MidasComm.Com>
Date: Tue, 17 Jan 2006 20:58:51 +0530 (IST)
In-reply-to: <00e501c61b75$a5f0c0a0$10eca8c0@grendel>
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
On Tue, 17 Jan 2006, Kevin D. Kissell wrote:

> > CPUs may have a variable CPU frequency which makes CPU counter not
> > usable as a timer source". Does it mean that, we can't do the CPU
> > Clock down in MIPS Processor??

> You were on the right track when you tried hacking mips_timer_ack(),
> but note that both cycles_per_jiffy and mips_hpt_frequency end up
> being used in Count-based time calculations.  If the board is
> rebooting when you tested your mod, it's probably because there's an
> error or a typo in your code.

Maybe. Started checking it by added few prink() to see the values of 
my_cycle_per_jiffy, cycles_per_jiffy and mips_hpt_frequency.

> Note that just changing the Count register increment will result in
> some small error each time the clock mode changes,

This is not an major probelm. But as you indicated, I will make some
modification in PMU driver to takecare the drift.

Thanks,
-- 
Bharathi S


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