On 10/12/07, Daniel Rossier <[EMAIL PROTECTED]> wrote:
> Gilles Chanteperdrix wrote:
> >  On 10/12/07, Daniel Rossier <[EMAIL PROTECTED]> wrote:
> > > Jan Kiszka wrote:
> > >> ROSSIER Daniel wrote:
> > >>> Hi everyone,
> > >>>
> > >>> I'm taking over the original thread from Patrick concerning the
> > >>>  port of Xenomai on Xscale with Linux 2.6.20. Briefly
> > >>> summarized, the boot process actually freezes after a while
> > >>> right after the nucleus has been started.
> > >>>
> > >>> I've investigated the issue over the last hours, and I came up
> > >>> with the following conclusion: it seems that the problem is due
> > >>> to a endless loop in do_gettimeofday in arch/arm/kernel/time.c.
> > >>> Here is the code:
> > >>>
> > >>> "... do { seq = read_seqbegin_irqsave(&xtime_lock, flags); usec
> > >>> = system_timer->offset(); sec = xtime.tv_sec; usec +=
> > >>> xtime.tv_nsec / 1000; } while
> > >>> (read_seqretry_irqrestore(&xtime_lock, seq, flags)); ..."
> > >>>
> > >>> If I remove the do { } while loop with the call to
> > >>> read_seqbegin_irqsave(), then the boot process is going ahead
> > >>> (I got a suspicious error like "I-pipe: Detected illicit call
> > >>> from domain 'Xenomai' " but it might well be normal with such a
> > >>>  modification.
> > >> Please post the full oops about that "illicit call". It may point
> > >> to an otherwise hidden invalid usage of Linux services over the
> > >> Xenomai domain and explain the lock-up.
> > > Sure; here is the output message: " I-pipe: Detected illicit call
> > > from domain 'Xenomai' into a service reserved for domain 'Linux'
> > > and below. [<c0027328>] (show_stack+0x0/0x40) from [<c005d590>]
> > > (ipipe_check_context+0x88/0xa4) [<c005d508>]
> > > (ipipe_check_context+0x0/0xa4) from [<c002d9e4>]
> > > (__ipipe_mach_set_dec+0x24/0x7c) r5 = 54503BD0  r4 = 00003029
> > > [<c002d9c0>] (__ipipe_mach_set_dec+0x0/0x7c) from [<c00681e0>]
> > > (xntimer_do_tick_aperiodic+0x2f4/0x33c) r4 = 00003029
> >
> >  This does not make sense, __ipipe_mach_set_dec is a very simple
> >  function that should not trigger this illicit call.
> >
>
> Exactly Gilles! Now I solved this bug. Having a look at the
> __ipipe_mach_set_dec() showed me
> an invokation to write_seqlock(&xtime_lock) !! I don't know why...
>
> As Philippe said, it is not allowed. I changed with
> local_irq_save_hw(flags) (as it is in the 2.6.15) and there is no
> deadlock anymore...

I read I-pipe 2.6.20 arm 1.7-06, and there is no
write_seq_lock(&xtime_lock) either. Are you sure the patch applied
cleanly ?


-- 
                                               Gilles Chanteperdrix

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