[PATCH] PCI: Quirk for ASUS S3 issue

[AceLan Kao <acelan.kao@canonical.com>]

Some of ASUS machines have problem to enter S3.
The root cause of this issue is result from the the BIOS will try to
disable USBs which was already disabled by driver.
BIOS will to check the EHCI command register, if it's not zero, then
BIOS will think the USB is not disabled yet, so it will try to disable
USB again.
To resolve this, we should clear the EHCI command register before
entering S3. And this does no harm to the system, since it'll switch
off the power after enter S3, so the value in memory is not important
at all.

Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
---
 drivers/pci/quirks.c    |   15 +++++++++++++++
 include/linux/pci_ids.h |    2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 194b243a..684cd1f 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2955,6 +2955,21 @@ static void __devinit asus_ehci_no_d3(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1c26, asus_ehci_no_d3);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1c2d, asus_ehci_no_d3);
 
+/*
+ * ASUS BIOS will check EHCI command register to see if USB if disabled
+ * or not. BIOS will try to disable USB if the command register is not
+ * cleared. But, actually, USB is disabled by the driver while entering S3,
+ * so it'll hang in BIOS when it try to disable USB.
+ * Since it's going to enter S3, so it does no harm to clear the command
+ * register.
+ */
+static void asus_clear_pci_command(struct pci_dev *dev)
+{
+	pci_write_config_word(dev, PCI_COMMAND, 0);
+}
+DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_HUDSON_EHCI, asus_clear_memory_bit);
+DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_EHCI, asus_clear_memory_bit);
+
 static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
 			  struct pci_fixup *end)
 {
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index ab741b0..e79c469 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -216,6 +216,7 @@
 #define PCI_DEVICE_ID_ATI_68800		0x4158
 #define PCI_DEVICE_ID_ATI_215CT222	0x4354
 #define PCI_DEVICE_ID_ATI_210888CX	0x4358
+#define PCI_DEVICE_ID_ATI_EHCI		0x4396
 #define PCI_DEVICE_ID_ATI_215ET222	0x4554
 /* Mach64 / Rage */
 #define PCI_DEVICE_ID_ATI_215GB		0x4742
@@ -553,6 +554,7 @@
 #define PCI_DEVICE_ID_AMD_8131_BRIDGE	0x7450
 #define PCI_DEVICE_ID_AMD_8131_APIC	0x7451
 #define PCI_DEVICE_ID_AMD_8132_BRIDGE	0x7458
+#define PCI_DEVICE_ID_AMD_HUDSON_EHCI	0x7808
 #define PCI_DEVICE_ID_AMD_HUDSON2_SMBUS	0x780b
 #define PCI_DEVICE_ID_AMD_CS5535_IDE    0x208F
 #define PCI_DEVICE_ID_AMD_CS5536_ISA    0x2090
-- 
1.7.9.5