>
> 2007-08-02 (木) の 14:32 -0500 に John Keller さんは書きました:
> > >
> > > Hi,
> > >
> > > This is FYI.
> > >
> > > If VECTOR_DOMAIN_PERCPU is NOT enabled:
> > >
> > > The "irq == vector" is always true in the following cases:
> > > - reserve_irq_vector(), which is used only by SN
> > > - create_irq() used on the system that has NO I/O SAPIC
> >
> > Could you say a bit more about this case. I see create_irq()
> > calling find_unassigned_vector() and find_unassigned_irq().
> > How is "irq == vector" guaranteed to be always true in this case?
> >
>
> Both find_unassigned_vector() and find_unassigned_irq() searchs the
> number from IA64_FIRST_DEVICE_VECTOR. And all irq and vector numbers
> from IA64_FIRST_DEVICE_VECTOR to IA64_LAST_DEVICE_VECTOR are not used.
>
> The create_irq() acquires both irq number and vector number using
> find_unassigned_irq() and find_unassigned_vector() respectively and
> bind them, with vector_lock held.
>
> The clear_irq_vector(), which is called through destroy_irq() and so
> on, frees both irq and vector with vector_lock held.
>
> Since oth irq and vector are acquired/freed at a time, "irq == vector"
> is guaranteed.
>
> But there is a exception destroy_and_reserve_irq(), which is called
> by IOSAPIC code. It frees both irq and vector, and reserve irq after
> that. That is, it only frees vector. This is required for fixed
> mapping between gsi and irq.
>
> Thanks,
> Kenji Kaneshige
Thanks for the info.
Your patch looks good to me, along with the other change to
sn_irq_to_vector().
> What about this:
>
> ia64_vector sn_irq_to_vector(int irq)
> {
> if (irq >= IA64_NUM_VECTORS)
> return 0;
> return (ia64_vector)irq;
> }
>
>
John Keller
>
>
> > John
> >
> >
> >
> > > - assign_irq_vector() with AUTO_ASSIGN specified
> > > - Vectors outside FIRST_DEVICE_VECTOR to LAST_DEVICE_VECTOR
> > >
> > > The "irq == vector" is not always true in the folliwng cases:
> > > - create_irq() used on the system that has I/O SAPICs.
> > > - assign_irq_vector() with the value other than AUTO_ASSIGN
> > > specified on the system has I/O SAPICs.
> > >
> > > And it is not ensured that those are true even in the future.
> > >
> > > Yasuaki, could you check if it is correct?
> > >
> > > Thanks,
> > > Kenji Kaneshige
> > >
> > >
> > >
> > > 2007-08-02 (木) の 08:26 -0500 に John Keller さんは書きました:
> > > > Yes, we'll take a look at it.
> > > >
> > > > John
> > > >
> > > >
> > > > >
> > > > > Hi Kenji-san
> > > > >
> > > > > I believe we need this property, but I am not 100% sure, so I am
> > > > > going to forward your patch to our team who maintain the IRQ code
> > > > > for Altix.
> > > > >
> > > > > Mike, Aaron or John, would one of you have time to take a look at
> > > > > this?
> > > > >
> > > > > Thanks,
> > > > > Jes
> > > > >
> > > > >
> > > > > Kenji Kaneshige wrote:
> > > > > > Hi Jes-san, Russ-san, Christoph-san and SN platform developers,
> > > > > >
> > > > > > I glanced over the SN code, and I found SN platform doesn't have SN
> > > > > > specific irq_to_vector() function, though it has SN specific
> > > > > > local_vector_to_irq() function. I guess it was OK because maybe SN
> > > > > > platform depends on irq == vector and old generic irq_to_vector() was
> > > > > > just returning the same value as irq.
> > > > > >
> > > > > > The irq_to_vector() function, however, has been changed by vector
> > > > > > domain support, and currently it can return the different value from
> > > > > > irq, even when VECTOR_DOMAIN_PERCPU is not enabled. This can happen
> > > > > > when an interrupt thorough I/O SAPIC is unregistered and another
> > > > > > interupt is registered. So if my guess (SN platform depends on irq ==
> > > > > > vector) is true, something problem might happen on SN platform when
> > > > > > PCI hotplugging or driver reloading.
> > > > > >
> > > > > > If it is true that SN platform depends on irq == vector, we need to
> > > > > > implement SN specific irq_to_vector() that returns the same value as
> > > > > > irq, I think. I made sample patches to implement platform specific
> > > > > > irq_to_vector() as follows. Note that [PATCH 2/2] is not tested yet
> > > > > > because I don't have any SN platform unfortunately.
> > > > > >
> > > > > > [PATCH 1/2] Add base support for platform_irq_to_vector()
> > > > > > [PATCH 2/2] Implement platform_irq_to_vector() for SN
> > > > > >
> > > > > > Could you give me comments?
> > > > > >
> > > > > > Thanks,
> > > > > > Kenji Kaneshige
> > > > > >
> > > > >
> > > > >
> > > >
> > > > -
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> >
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