From: Bjorn Helgaas Date: Wed, 29 Jan 2014 23:13:51 +0000 (-0700) Subject: PCI: Enable INTx if BIOS left them disabled X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1e2571a78138361f74afeb4c5df859b9536b2d8e;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git PCI: Enable INTx if BIOS left them disabled 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 Reported-and-tested-by: Jamie Chen Signed-off-by: Bjorn Helgaas CC: stable@vger.kernel.org CC: Sarah Sharp --- diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 52e10e1181d0..8dc3e701ec57 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1181,6 +1181,8 @@ 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) @@ -1190,6 +1192,14 @@ 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; }