From db8be50c4307dac2b37305fc59c8dc0f978d09ea Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Mon, 3 Aug 2009 12:40:27 +0100 Subject: [PATCH] USB: Work around BIOS bugs by quiescing USB controllers earlier We are seeing a number of crashes in SMM, when VT-d is enabled while 'Legacy USB support' is enabled in various BIOSes. The BIOS is supposed to indicate which addresses it uses for DMA in a special ACPI table ("RMRR"), so that we can punch a hole for it when we set up the IOMMU. The problem is, as usual, that BIOS engineers are totally incompetent. They write code which will crash if the DMA goes AWOL, and then they either neglect to provide an RMRR table at all, or they put the wrong addresses in it. And of course they don't do _any_ QA, since that would take too much time away from their crack-smoking habit. The real fix, of course, is for consumers to refuse to buy motherboards which only have closed-source firmware available. If we had _open_ firmware, bugs like this would be easy to fix. Since that's something I can only dream about, this patch implements an alternative -- ensuring that the USB controllers are handed off from the BIOS and quiesced _before_ the IOMMU is initialised. That would have been a much better design than this RMRR nonsense in the first place, of course. The bootloader has no business doing DMA after the OS has booted anyway. Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/pci-quirks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c index 83b5f9cea85a..23cf3bde4762 100644 --- a/drivers/usb/host/pci-quirks.c +++ b/drivers/usb/host/pci-quirks.c @@ -475,4 +475,4 @@ static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev) else if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI) quirk_usb_handoff_xhci(pdev); } -DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff); +DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff); -- 2.20.1