Time running

andrzej zaborowski balrogg at gmail.com
Mon Oct 6 00:51:57 CEST 2008


Hi,

2008/10/6 Balaji Rao <balaji at raobalaji.com>:
> On Wed, 01 Oct 2008 15:05:22 +0100
> Andy Green <andy at openmoko.com> wrote:
>> | How do I fix this ? I've noticed that the number of timer interrupts
>> | received is ~6x lesser. I wonder what the problem really is. Are the
>> | interrupts not delivered at the required rate and is there a way I
>> can | test this ?
>> |
>> | Suggestions welcome.
>>
>> I'm working on adding the andy-2.6.26 stuff to andy-tracking right now
>> and seeing the same.
>>
>> Previously (some weeks ago) on tracking there was trouble with hdq
>> that I put down to PWM init affecting the timer used for FIQ
>> generation.  I moved the FIQ timer to another PWM unit and the
>> problems went away. Since then FIQ is trashed by later changes
>> upstream I am trying to figure out now.
>>
>> Anyway I would dump the PWM-related registers from CPU on 2.6.24 or
>> 2.6.26 and current tracking and compare them, it seems it might give
>> a clue.
>
> Andy,
>
> I've narrowed down the problem to the following change upstream.

If you're still fighting the timer going too slow issue, apparently
it's seen on all S3C24xx machines except the Simtec ones (that use
tclk input) and it's been discussen on LAKML and there was a fix
posted:

http://marc.info/?t=122293014600003&r=1&w=2

I used this when developing the GENERIC_TIME / GENERIC_CLOCKEVENTS
support recently and it worked for me.
Cheers



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