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SubjectRe: [PATCH 3.8 23/81] PCI: Enable INTx if BIOS left them disabled
On Tue, Mar 25, 2014 at 11:15 AM, Kamal Mostafa <kamal@canonical.com> wrote:
> 3.8.13.20 -stable review patch. If anyone has any objections, please let me know.

If you pick up this one, you need the follow-up fix as well:

866d54177b4e671cd52bed1fb487d140d7b691f5 PCI: Enable INTx in
pci_reenable_device() only when MSI/MSI-X not enabled


> 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: Kamal Mostafa <kamal@canonical.com>
> ---
> drivers/pci/pci.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index d1b4e00..4235728 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1126,6 +1126,8 @@ EXPORT_SYMBOL_GPL(pci_load_and_free_saved_state);
> 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)
> @@ -1135,6 +1137,14 @@ static int do_pci_enable_device(struct pci_dev *dev, int bars)
> 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;
> }
>
> --
> 1.8.3.2
>


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