Re: [Xenomai-core] [PATCH] fix hw-timer setup/cleanup for i386

[Jan Kiszka <jan.kiszka@domain.hid>]

Stelian Pop wrote:
> Hi Jan,
> 
> [taking this on the list after several mails with Philippe...]
> 
> Le jeudi 11 octobre 2007 à 22:47 +0200, Jan Kiszka a écrit :
>> This patch for SVN trunk fixes most of the current bugs around hardware
>> timer takeover and release from/to Linux.
> [...]
> 
> I have a problem with the timer on my MacBook Pro (Core2Duo, used in
> _32_ bit mode)(*): when Xenomai takes over the timer (at 'modprobe
> xeno_native' time), the Linux timer stops.

Hmm, that's not too different from my own test setup.

> 
> Looking into /proc/xenomai/irq shows that Xenomai does receive the
> hardware interrupts, and /proc/interrupts shows that they are no longer
> forwarded to Linux. Before loading xeno_native, everything is ok.
> 
> Linux userspace continues to somewhat work: I can issue commands, and
> depending on the syscalls they made I suppose (no, strace doesn't work),
> sometimes they end correctly sometimes they hang (and I cannot interrupt
> them by ^C or other signals.).
> 
> I tried several .config variations, without any change in behaviour: my
> current test config has SMP, NO_HZ, APIC, PREEMPT, HIRES all disabled).
> 
> This happens with a 2.6.22.9 kernel, adeos-ipipe-2.6.22-i386-1.10-07,
> xenomai svn HEAD (rev 3050), with or without your current patch. It is
> quite possible that this is not a new problem, since I have this laptop
> since a few weeks only and I never ran Xenomai on it. 
> 
> I'll happily provide any further information or test results if you
> need.

/proc/xenomai/timerstat/master may provide further hints about the state
of the host timer (please keep my patch applied for this). Also, you
could take an I-pipe trace around the timer takeover and the following
few milliseconds, using the new trigger feature:

echo rthal_timer_request > /proc/ipipe/trace/trigger

BTW, does the latency test of Xenomai work?

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux