Messages in this thread |  | | | Date | Fri, 2 Oct 2009 21:28:32 +0200 | | From | Mikael Pettersson <> | | Subject | Re: Patch "USB: Work around BIOS bugs by quiescing USB controllers earlier" causes MCEs |
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Mikael Pettersson writes: > Nick Piggin writes: > > Hi, > > > > Your patch db8be50c4307dac2b37305fc59c8dc0f978d09ea is causing my > > ia64 Altix system to die with an MCE in early boot. > > The same commit has been confirmed by two people on the ARM list > to cause boot failures on two different Intel XScale IOP machines. > The machines have serial consoles, but only show > > Uncompressing Linux... done. Booting the kernel. > > before they hang.
I've just investigated this on one of my ARM boxes that this commit kills.
The commit changed quirk_usb_early_handoff to be a FIXUP_HEADER, which caused it to be invoked during the early stages of the platform's PCI init (arch/arm/kernel/bios32.c). quirk_usb_handoff_uhci() gets a bogus I/O base address, passes that down to uhci_reset_hc(), causing a kernel page fault in the first "outw(UHCI_USBCMD_HCRESET, base + UHCI_USBCMD);", causing the kernel to oops.
(All this occurs before the serial console works, so I had to add a platform-specific puts() and lots of tracing statements.)
Changing this quirk back to a FIXUP_FINAL allows the platform's PCI init to complete. Later on the generic pci_init() calls the quirk, which now gets the correct I/O base address, and the outw()s in uhci_reset_hc() don't fail.
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