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authorSarah Sharp2012-02-07 15:11:46 -0800
committerSarah Sharp2012-02-21 15:45:08 -0800
commitcab928ee1f221c9cc48d6615070fefe2e444384a (patch)
tree80922aa70a57cf99fb94df909beacfe56e6f2c0e /drivers
parentb9e44fe5ecda4158c22bc1ea4bffa378a4f83f65 (diff)
USB: Fix handoff when BIOS disables host PCI device.
On some systems with an Intel Panther Point xHCI host controller, the BIOS disables the xHCI PCI device during boot, and switches the xHCI ports over to EHCI. This allows the BIOS to access USB devices without having xHCI support. The downside is that the xHCI BIOS handoff mechanism will fail because memory mapped I/O is not enabled for the disabled PCI device. Jesse Barnes says this is expected behavior. The PCI core will enable BARs before quirks run, but it will leave it in an undefined state, and it may not have memory mapped I/O enabled. Make the generic USB quirk handler call pci_enable_device() to re-enable MMIO, and call pci_disable_device() once the host-specific BIOS handoff is finished. This will balance the ref counts in the PCI core. When the PCI probe function is called, usb_hcd_pci_probe() will call pci_enable_device() again. This should be back ported to kernels as old as 2.6.31. That was the first kernel with xHCI support, and no one has complained about BIOS handoffs failing due to memory mapped I/O being disabled on other hosts (EHCI, UHCI, or OHCI). Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Acked-by: Oliver Neukum <oneukum@suse.de> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/host/pci-quirks.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
index ac53a662a6a3..7732d69e49e0 100644
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -872,7 +872,17 @@ static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
*/
if (pdev->vendor == 0x184e) /* vendor Netlogic */
return;
+ if (pdev->class != PCI_CLASS_SERIAL_USB_UHCI &&
+ pdev->class != PCI_CLASS_SERIAL_USB_OHCI &&
+ pdev->class != PCI_CLASS_SERIAL_USB_EHCI &&
+ pdev->class != PCI_CLASS_SERIAL_USB_XHCI)
+ return;
+ if (pci_enable_device(pdev) < 0) {
+ dev_warn(&pdev->dev, "Can't enable PCI device, "
+ "BIOS handoff failed.\n");
+ return;
+ }
if (pdev->class == PCI_CLASS_SERIAL_USB_UHCI)
quirk_usb_handoff_uhci(pdev);
else if (pdev->class == PCI_CLASS_SERIAL_USB_OHCI)
@@ -881,5 +891,6 @@ static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
quirk_usb_disable_ehci(pdev);
else if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI)
quirk_usb_handoff_xhci(pdev);
+ pci_disable_device(pdev);
}
DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff);