x86/PCI: Avoid AMD SB7xx EHCI USB wakeup defect

On an AMD Carrizo laptop, when EHCI runtime PM is enabled, EHCI ports do
not assert PME# for device plug/unplug events while in D3.

As Alan Stern points out [1], the PME signal is not enabled when controller
is in D3, therefore it's not being woken up when new devices get plugged
in.

Testing shows PME signal works when the EHCI power state is D2.

Clear the PCI_PM_CAP_PME_D3 and PCI_PM_CAP_PME_D3cold bits in
dev->pme_support to indicate the device will not assert PME# from those
states.

[1] http://lkml.kernel.org/r/Pine.LNX.4.44L0.1706121010010.2092-100000@iolanthe.rowland.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196091
Link: https://support.amd.com/TechDocs/46837.pdf
Link: https://support.amd.com/TechDocs/42413.pdf
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
[bhelgaas: changelog, add parens in quirk]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index 6d52b94f4bb915d119e16da1628743b93fa7af39..2259acdcede5f4112673544c1f9e046e52f9c235 100644 (file)
--- a/arch/x86/pci/fixup.c
+++ b/arch/x86/pci/fixup.c
@@ -571,3 +571,18 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, pci_invalid_bar);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6f60, pci_invalid_bar);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fa0, pci_invalid_bar);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, pci_invalid_bar);
+
+/*
+ * Device [1022:7808]
+ * 23. USB Wake on Connect/Disconnect with Low Speed Devices
+ * https://support.amd.com/TechDocs/46837.pdf
+ * Appendix A2
+ * https://support.amd.com/TechDocs/42413.pdf
+ */
+static void pci_fixup_amd_ehci_pme(struct pci_dev *dev)
+{
+       dev_info(&dev->dev, "PME# does not work under D3, disabling it\n");
+       dev->pme_support &= ~((PCI_PM_CAP_PME_D3 | PCI_PM_CAP_PME_D3cold)
+               >> PCI_PM_CAP_PME_SHIFT);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x7808, pci_fixup_amd_ehci_pme);