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Date: Tue, 22 May 2007 17:56:44 -0700 From: Jesse Barnes <jbarnes@...tuousgeek.org> To: Robert Hancock <hancockr@...w.ca> Cc: Olivier Galibert <galibert@...ox.com>, linux-kernel <linux-kernel@...r.kernel.org>, Andi Kleen <ak@...e.de>, Chuck Ebbert <cebbert@...hat.com>, Len Brown <lenb@...nel.org> Subject: Re: [RFC PATCH] PCI MMCONFIG: add validation against ACPI motherboard resources On Tuesday, May 22, 2007, Robert Hancock wrote: > Jesse Barnes wrote: > > On Tuesday, May 22, 2007, Robert Hancock wrote: > >> Eww. I don't see where we disable the decode at all while we probe > >> the BARs on the device. That seems like a bad thing, especially with > >> the way we probe 64-bit BARs (do the low 32 bits first and then the > >> high 32 bits). This means the base address effectively gets set to > >> 0xfffffff0 momentarily, which might cause some issues. > > > > I'm a bit shocked that things work as well as they do without the > > disabling... > > > >> I'd try adding some code inside pci_setup_device > >> (drivers/pci/probe.c) to disable PCI_COMMAND_IO and > >> PCI_COMMAND_MEMORY on the device when probing devices with the > >> standard header type and then restoring the previous command bits > >> afterwards, and see what effect that has. It'll be interesting if it > >> does, since obviously it seems to work as it is with non-MMCONFIG > >> access methods. Maybe the base address being set like that interferes > >> with MMCONFIG access itself somehow? > > > > I tried that, and it seems to get past probing the graphics device at > > least, but it hangs a bit later. It could be that the enable/disable > > I added wasn't correct though, I didn't check to see which one I > > should disable in the command word, which may be a problem (just > > disabled them both every probe). I'll try again with more precise > > enable/disable semantics. > > It'd be interesting to see at what access it ran into trouble next, at > least if it's consistent. Could be that some device doesn't like having > the decode disabled.. I think it actually gets through the probing but hangs elsewhere, but I'll have to test again to be sure. Jesse - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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