Re: [PATCH] Fix USB suspend/resume crasher

From: Nigel Cunningham
Date: Tue Nov 22 2005 - 23:51:33 EST


On Wed, 2005-11-23 at 14:08, Benjamin Herrenschmidt wrote:
> This is my latest patch against current linus -git, it closes the IRQ
> race and makes various other OHCI & EHCI code path safer vs.
> suspend/resume. I've been able to (finally !) successfully suspend and
> resume various Mac models, with or without USB mouse plugged, or
> plugging while asleep, or unplugging while asleep etc... all without a
> crash. There are still some races here or there in the USB code, but at
> least the main cause of crash is now fixes by this patch (access to a
> controller that has been suspended, due to either shared interrupts or
> other code path).
> I haven't fixed UHCI as I don't have any HW to test, though I hope I
> haven't broken it neither. Alan, I would appreciate if you could have a
> look.
> This patch applies on top of the patch that moves the PowerMac specific
> code out of ohci-pci.c to hcd-pci.c where it belongs. This patch isn't
> upstream yet for reasons I don't fully understand (why does USB stuffs
> has such a high latency for going upstream ?), I'm sending it as a reply
> to this email for completeness.
> Without this patch, you cannot reliably sleep/wakeup any recent Mac, and
> I suspect PCs have some more sneaky issues too (they don't frankly crash
> with machine checks because x86 tend to silently swallow PCI errors but
> that won't last afaik, at least PCI Express will blow up in those
> situations, but the USB code may still misbehave).

Sounds great. Maybe I'll finally be able to change my first question to
people with suspend problems from: "Do you have USB built as modules and
unloaded while suspending."



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