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    SubjectRe: [PATCH 3.4 30/99] PCI: Enable INTx if BIOS left them disabled
    [+cc Andreas]

    On Fri, Mar 7, 2014 at 6:07 PM, Greg Kroah-Hartman
    <gregkh@linuxfoundation.org> wrote:
    > 3.4-stable review patch. If anyone has any objections, please let me know.

    Let's hold off on this for a bit. Andreas found that this patch
    breaks pciehp, and we haven't figured out the best fix yet.

    http://lkml.kernel.org/r/CAMxnaaXd9-VbxSYa9q1YVT+fwfDFYKGG2Hq-1jkc-awLX-HwtQ@mail.gmail.com
    https://bugzilla.kernel.org/show_bug.cgi?id=71691

    > ------------------
    >
    > From: Bjorn Helgaas <bhelgaas@google.com>
    >
    > commit 1f42db786b14a31bf807fc41ee5583a00c08fcb1 upstream.
    >
    > Some firmware leaves the Interrupt Disable bit set even if the device uses
    > INTx interrupts. Clear Interrupt Disable so we get those interrupts.
    >
    > Based on the report mentioned below, if the user selects the "EHCI only"
    > option in the Intel Baytrail BIOS, the EHCI device is handed off to the OS
    > with the PCI_COMMAND_INTX_DISABLE bit set.
    >
    > Link: http://lkml.kernel.org/r/20140114181721.GC12126@xanatos
    > Link: https://bugzilla.kernel.org/show_bug.cgi?id=70601
    > Reported-by: Chris Cheng <chris.cheng@atrustcorp.com>
    > Reported-and-tested-by: Jamie Chen <jamie.chen@intel.com>
    > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    > CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
    > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    >
    > ---
    > drivers/pci/pci.c | 10 ++++++++++
    > 1 file changed, 10 insertions(+)
    >
    > --- a/drivers/pci/pci.c
    > +++ b/drivers/pci/pci.c
    > @@ -1133,6 +1133,8 @@ EXPORT_SYMBOL_GPL(pci_load_and_free_save
    > static int do_pci_enable_device(struct pci_dev *dev, int bars)
    > {
    > int err;
    > + u16 cmd;
    > + u8 pin;
    >
    > err = pci_set_power_state(dev, PCI_D0);
    > if (err < 0 && err != -EIO)
    > @@ -1142,6 +1144,14 @@ static int do_pci_enable_device(struct p
    > return err;
    > pci_fixup_device(pci_fixup_enable, dev);
    >
    > + pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
    > + if (pin) {
    > + pci_read_config_word(dev, PCI_COMMAND, &cmd);
    > + if (cmd & PCI_COMMAND_INTX_DISABLE)
    > + pci_write_config_word(dev, PCI_COMMAND,
    > + cmd & ~PCI_COMMAND_INTX_DISABLE);
    > + }
    > +
    > return 0;
    > }
    >
    >
    >


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