On Wed, 11 Apr 2012 15:29:42 +1000, Benjamin Herrenschmidt <b...@kernel.crashing.org> wrote: > On Wed, 2012-04-11 at 11:33 +1000, Benjamin Herrenschmidt wrote: > > On Wed, 2012-04-11 at 11:13 +1000, Benjamin Herrenschmidt wrote: > > > On Sat, 2012-04-07 at 14:27 +0200, Andreas Schwab wrote: > > > > Benjamin Herrenschmidt <b...@kernel.crashing.org> writes: > > > > > > > > > It's arguable that this irq_set_irq_type(,NONE) shouln't be there but > > > > > still ... it's been around for ever and things worked :-) So something > > > > > -else- is causing the problem and I'd like to understand what exactly. > > > > > > > > AFAICS before a09b659cd68c10ec6a30cb91ebd2c327fcd5bfe5 > > > > irq_set_irq_type(,NONE) was actually a no-op. > > > > > > So I'm still a bit baffled... ie, I understand some of what's happening > > > but not why it breaks things, I haven't yet managed to reproduce but I > > > haven't tried too hard just yet (was away from the HW) : > > > > Allright, I have a repro-case, I'll dig. > > Ok, so it's Grant's fault :-)
I pretty much expected it would be. :-p > So basically, it's quite subtle and I'm only 99% sure of the details but > I believe what happens is: > > - The audio interrupts get virq 64 and 65 (so above NR_IRQS) > > - The reverse map isn't pre-filled at map time (we should probably do > it nowadays), we do it lazily so ... Hmmm... I though I had merged a patch that does that. /me goes to look again... Okay, I did write that patch, but I never merged it because it didn't get much review and I was already nervous about the other irq_domain changes. I'll post it again and ask for feedback. > - The whole business with irq_virq_count needs fixing. Basically the > default value shouldn't be NR_IRQ. I suggest making it 0 and have all > the use sites do something like: > > max = irq_virq_count ? irq_virq_count : nr_irqs; > > (Grant, can you take care of that ?) Yeah, I've got a different way to fix it though. There is exactly one user of irq_virq_count in-tree right now: PS3. Also, irq_virq_count is only useful for the NOMAP mapping. So, instead of having a single global irq_virq_count values, I've dropped it entirely and added a max_irq argument to irq_domain_add_nomap(). That makes it a property of an individual nomap irq domain instead of a global system settting. Hopefully I'll have a draft patch ready today. g. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
