On Tue, Aug 14, 2012 at 04:44:49PM -0400, Matthew Garrett wrote:
> My test platform (Intel DX79SI) boots reliably under BIOS, but frequently
> crashes when booting via UEFI. I finally tracked this down to the xhci
> handoff code. It seems that reads from the device occasionally just return
> 0xff, resulting in xhci_find_next_cap_offset generating a value that's
> larger than the resource region. We then oops when attempting to read the
> value. Sanity checking that value lets us avoid the crash.
>
> I've no idea what's causing the underlying problem, and xhci still doesn't
> actually *work* even with this, but the machine at least boots which will
> probably make further debugging easier.
Is this an Ivy Bridge system? xHCI may not work because you're skipping
the port switchover code just before the hc_init label. Of course, if
the host controller continues to report all f's for register values,
there's no point in trying to initialize the host at all...
Sarah Sharp
>
> Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
> ---
> drivers/usb/host/pci-quirks.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/host/pci-quirks.c b/drivers/usb/host/pci-quirks.c
> index df0828c..7cda232 100644
> --- a/drivers/usb/host/pci-quirks.c
> +++ b/drivers/usb/host/pci-quirks.c
> @@ -815,12 +815,12 @@ static void __devinit quirk_usb_handoff_xhci(struct pci_dev *pdev)
> void __iomem *op_reg_base;
> u32 val;
> int timeout;
> + int len = pci_resource_len(pdev, 0);
>
> if (!mmio_resource_enabled(pdev, 0))
> return;
>
> - base = ioremap_nocache(pci_resource_start(pdev, 0),
> - pci_resource_len(pdev, 0));
> + base = ioremap_nocache(pci_resource_start(pdev, 0), len);
> if (base == NULL)
> return;
>
> @@ -830,9 +830,17 @@ static void __devinit quirk_usb_handoff_xhci(struct pci_dev *pdev)
> */
> ext_cap_offset = xhci_find_next_cap_offset(base, XHCI_HCC_PARAMS_OFFSET);
> do {
> + if ((ext_cap_offset + sizeof(val)) > len) {
> + /* We're reading garbage from the controller */
> + dev_warn(&pdev->dev,
> + "xHCI controller failing to respond");
> + return;
> + }
> +
> if (!ext_cap_offset)
> /* We've reached the end of the extended capabilities */
> goto hc_init;
> +
> val = readl(base + ext_cap_offset);
> if (XHCI_EXT_CAPS_ID(val) == XHCI_EXT_CAPS_LEGACY)
> break;
> --
> 1.7.11.2
>
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