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    SubjectRe: 3c59x vortex_timer rt hack (was: rt20 patch question)
    Steven Rostedt <rostedt@goodmis.org> wrote:
    >
    >
    >
    > On Fri, 12 May 2006, Ingo Molnar wrote:
    >
    > > --- linux-rt.q.orig/drivers/net/3c59x.c
    > > +++ linux-rt.q/drivers/net/3c59x.c
    > > @@ -1897,7 +1897,8 @@ vortex_timer(unsigned long data)
    > >
    > > if (vp->medialock)
    > > goto leave_media_alone;
    > > - disable_irq(dev->irq);
    > > + /* hack! */
    > > + disable_irq_nosync(dev->irq);
    > > old_window = ioread16(ioaddr + EL3_CMD) >> 13;
    > > EL3WINDOW(4);
    > > media_status = ioread16(ioaddr + Wn4_Media);
    >
    > BTW, I originally thought about having Mark do this, but I'm nervious
    > about the side effects that this might have. Basically, it's doing
    > ioreads from the device while the interrupt could be doing iowrites.
    >
    > I don't know the device well enough to know if this is a problem.
    > I've added Andrew Morton to the CC list, since his name is all over the
    > code.
    >
    > Andrew,
    >
    > Do you know off hand what the side-effects to the vortex card might be
    > if we use disable_irq_nosync instead of disable_irq?
    >

    ooh, ow, sorry, that's lost in the mists of time. I don't know why we're
    doing disable_irq() in there.

    Whatever it does, I think you could take vp->lock instead - that'll stop
    the interrupt handler from doing anything if it does get entered while this
    CPU is running vortex_timer().

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