[PATCH v2 3/3] Add spurious wakeup quirk for LynxPoint-LP controllers

[Mathias Nyman <mathias.nyman@linux.intel.com>]

From: Laura Abbott <labbott@fedoraproject.org>

We received several reports of systems rebooting and powering on
after an attempted shutdown. Testing showed that setting
XHCI_SPURIOUS_WAKEUP quirk in addition to the XHCI_SPURIOUS_REBOOT
quirk allowed the system to shutdown as expected for LynxPoint-LP
xHCI controllers. Set the quirk back.

Note that the quirk was originally introduced for LynxPoint and
LynxPoint-LP just for this same reason. See:

commit 638298dc66ea ("xhci: Fix spurious wakeups after S5 on Haswell")

It was later limited to only concern HP machines as it caused
regression on some machines, see both bug and commit:

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=66171
commit 6962d914f317 ("xhci: Limit the spurious wakeup fix only to HP machines")

Later it was discovered that the powering on after shutdown
was limited to LynxPoint-LP (Haswell-ULT) and that some non-LP HP
machine suffered from spontaneous resume from S3 (which should
not be related to the SPURIOUS_WAKEUP quirk at all). An attempt
to fix this then removed the SPURIOUS_WAKEUP flag usage completely.

commit b45abacde3d5 ("xhci: no switching back on non-ULT Haswell")

Current understanding is that LynxPoint-LP (Haswell ULT) machines
need the SPURIOUS_WAKEUP quirk, otherwise they will restart, and
plain Lynxpoint (Haswell) machines may _not_ have the quirk
set otherwise they again will restart.

Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Oliver Neukum <oneukum@suse.com>
[Added more history to commit message -Mathias]
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index c79d336..c47d3e4 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -147,6 +147,7 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
 		pdev->device == PCI_DEVICE_ID_INTEL_LYNXPOINT_LP_XHCI) {
 		xhci->quirks |= XHCI_SPURIOUS_REBOOT;
+		xhci->quirks |= XHCI_SPURIOUS_WAKEUP;
 	}
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
 		(pdev->device == PCI_DEVICE_ID_INTEL_SUNRISEPOINT_LP_XHCI ||
-- 
1.9.1