[Xenomai-core] ARM IXP: ipipe regression from 2.6.31 to .33 and .35

[Richard Cochran <richardcochran@domain.hid>]

I have been trying to bring my IXP425 based system up to date, and I
have found an apparent regression. Everything worked fine with ipipe
2.6.30 and Xenomai 2.4. With 2.6.31 an ipipe kernel still boots, but
starting with 2.6.33 the trouble begins (see below).

I see that Gilles refactored the TSC emulation starting with
2.6.33. I wonder whether this could be the cause?

I did not immediately see any obvious bug, but I don't fully
understand the newer TSC code. I would appreciate any hints.

Thanks,
Richard

** ipipe-2.6.31-arm-1.16-01

   Seems to boot fine.

** ipipe-2.6.33-arm-1.18-01

   Boots, but runs very slowly. FCSE on/off makes no difference.
   After a few seconds, it seem to hand, but it might just be very
   slow. Once I saw this on the console:

      hrtimer: interrupt took 1414795601278721 ns

   coming from kernel/hrtimer.c:1363

      printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n", ...)

** ipipe-2.6.35.9-arm-1.18-01

   Does not boot with ipipe. FCSE on/off makes no difference.
   It *does* boot without ipipe enabled.