Hello.
Ingo Molnar wrote:
* Daniel Walker <[email protected]> wrote:
Pay close attention to the fasteoi interrupt threading. I added usage
of mask/unmask instead of using level handling, which worked well on
PPC.
this is wrong - it should be doing mask+ack.
It's what it was doing effectively. And what was wrong was calling ack()
which OpenPIC driver didn't (and was not obliged to) support.
also note that you changed:
- goto out_unlock;
to:
+ goto out;
and you even tried to hide your tracks:
out:
desc->chip->eoi(irq);
-out_unlock:
spin_unlock(&desc->lock);
:-)
really, the ->eoi() op should only be called for true fasteoi cases.
Why is that? eoi() is effectively the same as ack() in this case. I must
note that what's the "standard" 8259 driver is doing in mask_ack() seems
misleading since it actually masks IRQ and sends EOI there.
What we want here is to turn the fasteoi handler into a handler that
does mask+ack and then unmask. Not 'mask+eoi ... unmask' as your patch
does.
That's effectively the same for OpenPIC. Maybe that implemetation just
didn't look graceful but it was *correct*. And the current one is at least
incomplete.
I can see 3 ways to get out of this situation now:
1. Revert this change and use mask() + eoi() approach suggested by Daniel.
2. Add the ack() handler to OpenPIC driver -- and point it to mpic_eoi().
3. Do the same as x86 APIC driver does and use level/egde flows instead of
fasteoi for the case when IRQs are threaded -- that ensues doing (2) as well.
Note that all three aproaches lead to the effectively the same behavior
WRT OpenPIC (except for the edge-triggered IRQs in 3rd case). Opinions?
Ingo
WBR, Sergei
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
