[PATCH v5 06/27] irq_domain/powerpc: eliminate irq_map; use irq_alloc_desc() instead

[Grant Likely]

On Mon, 02 Apr 2012 18:29:15 +0200, Andreas Schwab <schwab at linux-m68k.org> wrote:
> Andreas Schwab <schwab at linux-m68k.org> writes:
> 
> > Grant Likely <grant.likely at secretlab.ca> writes:
> >
> >> This patch drops the powerpc-specific irq_map table and replaces it with
> >> directly using the irq_alloc_desc()/irq_free_desc() interfaces for allocating
> >> and freeing irq_desc structures.
> >
> > This breaks irqs on PowerMac G5.  I see lost irq errors from the sata
> > driver.
> 
> When I revert a09b659cd68c10ec6a30cb91ebd2c327fcd5bfe5 ("genirq: Fix
> long-term regression in genirq irq_set_irq_type() handling") on top of
> 3.4-rc1 the sata irq errors disappear, but I see a lot of spurious
> interrupts.  Also the X server is broken somehow, though I don't know
> whether that is related or a different bug.

That change is:

@@ -61,8 +61,7 @@ int irq_set_irq_type(unsigned int irq, unsigned int type)
                return -EINVAL;
 
        type &= IRQ_TYPE_SENSE_MASK;
-       if (type != IRQ_TYPE_NONE)
-               ret = __irq_set_trigger(desc, irq, type);
+       ret = __irq_set_trigger(desc, irq, type);
        irq_put_desc_busunlock(desc, flags);
        return ret;

So presumably irq_set_irq_type() is getting called with type ==
IRQ_TYPE_NONE.  From Russell's description, presumably that would mean
the G5 sata driver isn't setting the correct type for the interrupt,
but I have *no* idea how that intersects with the change removing the
powerpc irq map.

Can you dump out /debug/powerpc/virq_mapping from both before and
after the irq_map patch is applied?

g.