>>> On 20.03.13 at 12:55, Sander Eikelenboom <linux@eikelenboom.it> wrote:
> Close but not entirely ;)

Close to not crashing, maybe, but whether this really helps with your
problem is still entirely unclear.

> See attached serial log

Okay, I wasn't even aware of that assertion in _spin_lock_irq().

Keir, do you really think this is necessary? In the prior patch
version, handle_hpet_broadcast() had a flow like this

    spin_lock_irqsave();
    ...
    spin_unlock_irqrestore();
    ...
    if ( next_event != STIME_MAX )
    {
        spin_lock_irq();
        ...
        spin_unlock_irqrestore();
    }

avoiding the saving of the flags in the second lock acquire. Said
assertion makes it impossible to do this.

Sander, in any case, attached a fixed version of the patch (I had
to guess which of the two spin_lock_irq() calls it was, as the log
was incomplete in that the stack trace got dropped, but am pretty
positive that it was the one in handle_hpet_broadcast()).

Jan