Re: [PATCH RT] ehea: make receive irq handler non-threaded(IRQF_NODELAY)

From: Michael Ellerman
Date: Wed May 19 2010 - 21:34:15 EST

On Wed, 2010-05-19 at 23:08 +0200, Thomas Gleixner wrote:
> On Wed, 19 May 2010, Thomas Gleixner wrote:
> > > I'm still not clear on why the ultimate solution wasn't to have XICS report
> > > edge triggered as edge triggered. Probably some complexity of the entire power
> > > stack that I am ignorant of.
> > >
> > > > Apart from the issue of loosing interrupts there is also the fact that
> > > > masking on the XICS requires an RTAS call which takes a global lock.
> >
> > Right, I'd love to avoid that but with real level interrupts we'd run
> > into an interrupt storm. Though another solution would be to issue the
> > EOI after the threaded handler finished, that'd work as well, but
> > needs testing.
> Thought more about that. The case at hand (ehea) is nasty:
> The driver does _NOT_ disable the rx interrupt in the card in the rx
> interrupt handler - for whatever reason.

Yeah I saw that, but I don't know why it's written that way. Perhaps
Jan-Bernd or Doug will chime in and enlighten us? :)


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