[PATCH] USB: EHCI and NF2 quirk

This teaches the EHCI driver about a quirk seen in older NForce2 chips,
adding a workaround to ignore selective suspend requests.  Bus-wide
(so-called "global") suspend still works, as does USB wakeup of a
root hub that's globally suspended.

There's still a hole in this support though.  Strictly speaking, this
should _fail_ selective suspend requests, rather than ignoring them,
since doing it this way means that devices which should be able to issue
remote wakeup are not going to be able to do that.  For now, we'll just
live with that problem ... since usbcore expects to do selective suspend
on the way towards a full bus suspend, and usbcore needs to be able to
do full bus suspend.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 3a6687df5594..1e03f1a5a5fd 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -106,11 +106,11 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 		}
 		break;
 	case PCI_VENDOR_ID_NVIDIA:
+		switch (pdev->device) {
 		/* NVidia reports that certain chips don't handle
 		 * QH, ITD, or SITD addresses above 2GB.  (But TD,
 		 * data buffer, and periodic schedule are normal.)
 		 */
-		switch (pdev->device) {
 		case 0x003c:	/* MCP04 */
 		case 0x005b:	/* CK804 */
 		case 0x00d8:	/* CK8 */
@@ -120,6 +120,14 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 				ehci_warn(ehci, "can't enable NVidia "
 					"workaround for >2GB RAM\n");
 			break;
+		/* Some NForce2 chips have problems with selective suspend;
+		 * fixed in newer silicon.
+		 */
+		case 0x0068:
+			pci_read_config_dword(pdev, PCI_REVISION_ID, &temp);
+			if ((temp & 0xff) < 0xa4)
+				ehci->no_selective_suspend = 1;
+			break;
 		}
 		break;
 	}
@@ -163,6 +171,21 @@ static int ehci_pci_setup(struct usb_hcd *hcd)
 			device_init_wakeup(&pdev->dev, 1);
 	}
 
+#ifdef	CONFIG_USB_SUSPEND
+	/* REVISIT: the controller works fine for wakeup iff the root hub
+	 * itself is "globally" suspended, but usbcore currently doesn't
+	 * understand such things.
+	 *
+	 * System suspend currently expects to be able to suspend the entire
+	 * device tree, device-at-a-time.  If we failed selective suspend
+	 * reports, system suspend would fail; so the root hub code must claim
+	 * success.  That's lying to usbcore, and it matters for for runtime
+	 * PM scenarios with selective suspend and remote wakeup...
+	 */
+	if (ehci->no_selective_suspend && device_can_wakeup(&pdev->dev))
+		ehci_warn(ehci, "selective suspend/wakeup unavailable\n");
+#endif
+
 	retval = ehci_pci_reinit(ehci, pdev);
 done:
 	return retval;