Re: lockdep and threaded IRQs (was: ...)

David Brownell
2009-03-02T23:29:22Z

On Monday 02 March 2009, Peter Zijlstra wrote:
> > But if that's what is keeping you from fixing the lockdep bug,
> > why haven't you submitted patches to remove IRQF_DISABLED from
> > the kernel, and update all the drivers relying on IRQs being
> > enabled when their handlers run?
>
> I did so today. Just didn't realize things actually relied on it since
> lockdep turned them off and my system has been working fine.

That patch did no such thing. It added a BUG_ON(),
which has nothing to do with removing IRQF_DISABLED.

> Your driver needs threaded interrupts, Thomas is working on that now,
> and I saw a conversion of your driver to use that.

Thomas hasn't yet touched the issue of how to chain such IRQs
though ... I consider his v2 patches a decent start, with some
limitations that could be attributed to an x86 focus.

> IDE PIO can hopefully also be converted to threaded interrupts.

I have worked with ARMs with IDE support. That's become
rare in new chips though, even for CF cards; it needs too
many signal wires.

- Dave