[PATCH 3.10 59/85] PCI: Enable INTx in pci_reenable_device() only when MSI/MSI-X not enabled

Greg Kroah-Hartman
2014-03-21T00:30:17Z

From: Bjorn Helgaas <bhelgaas@google.com>

commit 3cdeb713dc66057b50682048c151eae07b186c42 upstream.

Andreas reported that after 1f42db786b14 ("PCI: Enable INTx if BIOS left
them disabled"), pciehp surprise removal stopped working.

This happens because pci_reenable_device() on the hotplug bridge (used in
the pciehp_configure_device() path) clears the Interrupt Disable bit, which
apparently breaks the bridge's MSI hotplug event reporting.

Previously we cleared the Interrupt Disable bit in do_pci_enable_device(),
which is used by both pci_enable_device() and pci_reenable_device(). But
we use pci_reenable_device() after the driver may have enabled MSI or
MSI-X, and we *set* Interrupt Disable as part of enabling MSI/MSI-X.

This patch clears Interrupt Disable only when MSI/MSI-X has not been
enabled.

Fixes: 1f42db786b14 PCI: Enable INTx if BIOS left them disabled
Link: https://bugzilla.kernel.org/show_bug.cgi?id=71691
Reported-and-tested-by: Andreas Noever <andreas.noever@gmail.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 | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1130,6 +1130,9 @@ static int do_pci_enable_device(struct p
return err;
pci_fixup_device(pci_fixup_enable, dev);

+ if (dev->msi_enabled || dev->msix_enabled)
+ return 0;
+
pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
if (pin) {
pci_read_config_word(dev, PCI_COMMAND, &cmd);