| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
Re: [Xen-devel] Re: [PATCH] xen: do not clear and mask evtchns in __xen_
On Tue, 5 Apr 2011, Ian Campbell wrote:
> Since this patch revolves around the interaction with the irq core I
> think it would be worth running it by tglx as well as xen-devel for the
> next iteration.
>
Yes, I'll do that.
> Does something about the switch of handler type fix the issue with
> drivers which call disable_irq() in their interrupt handler and leave it
> disabled until a later time? (e.g. the userspace evtchn driver). I think
> I know why this is the case but it would be useful to mention in the
> commit message.
Yep, I added a note in the commit message:
"it fixes a problem occurring when a driver calls disable_irq() in its
handler: the old code was unconditionally unmasking the evtchn even if
the irq is disabled when irq_eoi was called"
> On Mon, 2011-04-04 at 17:46 +0100, Stefano Stabellini wrote:
> >
> > - it uses these handlers in the same way Linux would use them: it let
> > Linux mask\unmask and ack the irq when Linux want to mask\unmask and ack
> > the irq;
>
> This code is in Linux, perhaps you mean "the same way native code would
> use them" or "with the semantics which the generic code defines" or
> something along those lines.
good point
> > + pirq_query_unmask(irq);
> > + /* we try to follow the same convention as Linux on native:
>
> That's basically a coincidence, isn't it?
>
> What we are actually trying to do is use the handler with the
> appropriate semantics for the type of interrupt, e.g. event channels are
> naturally edge triggered but some event channels can be bound to pirqs
> with configurations that require an EOI and therefore have a level of
> levelness about them.
I completely rewrote the paragraph, adding many more details, including
the Xen side of the interface.
>
> > + * handle_edge_irq for edge irqs and handle_fasteoi_irq for level
> > + * irqs
>
> should probably mention the relationship between pirq_needs_eoi=>level
> triggering.
done.
> Is there any relationship between pirq_needs_eoi and the trigger value
> passed to PHYSDEVOP_setup_gsi at setup time?
PHYSDEVOP_setup_gsi tells Xen the trigger value of the physical
interrupt, depending on this value Xen will handle the interrupt
differently. Besides Xen used to set the need_eoi flag of the
corresponding irq depending on the real trigger value of the underlying
physical interrupt, but it doesn't anymore.
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home