USB: OHCI: fix problem with global suspend on ATI controllers

Some OHCI controllers from ATI/AMD seem to have difficulty with
"global" USB suspend, that is, suspending an entire USB bus without
setting the suspend feature for each port connected to a device. When
we try to resume the child devices, the controller gives timeout
errors on the unsuspended ports, requiring resets, and can even cause
ohci-hcd to hang; see

http://marc.info/?l=linux-usb&m=139514332820398&w=2

and the following messages.

This patch fixes the problem by adding a new quirk flag to ohci-hcd.
The flag causes the ohci_rh_suspend() routine to suspend each
unsuspended, enabled port before suspending the root hub. This
effectively converts the "global" suspend to an ordinary root-hub
suspend. There is no need to unsuspend these ports when the root hub
is resumed, because the child devices will be resumed anyway in the
course of a normal system resume ("global" suspend is never used for
runtime PM).

This patch should be applied to all stable kernels which include
commit 0aa2832dd0d9 (USB: use "global suspend" for system sleep on
USB-2 buses) or a backported version thereof.

Signed-off-by: Alan Stern <[e-mail]>
Reported-by: Peter Münster <[e-mail]>
Tested-by: Peter Münster <[e-mail]>
CC: <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/ohci-hub.c

···
 	dl_done_list (ohci);
 	finish_unlinks (ohci, ohci_frame_no(ohci));
 
+	/*
+	 * Some controllers don't handle "global" suspend properly if
+	 * there are unsuspended ports.  For these controllers, put all
+	 * the enabled ports into suspend before suspending the root hub.
+	 */
+	if (ohci->flags & OHCI_QUIRK_GLOBAL_SUSPEND) {
+		__hc32 __iomem	*portstat = ohci->regs->roothub.portstatus;
+		int		i;
+		unsigned	temp;
+
+		for (i = 0; i < ohci->num_ports; (++i, ++portstat)) {
+			temp = ohci_readl(ohci, portstat);
+			if ((temp & (RH_PS_PES | RH_PS_PSS)) ==
+					RH_PS_PES)
+				ohci_writel(ohci, RH_PS_PSS, portstat);
+		}
+	}
+
 	/* maybe resume can wake root hub */
 	if (ohci_to_hcd(ohci)->self.root_hub->do_remote_wakeup || autostop) {
 		ohci->hc_control |= OHCI_CTRL_RWE;

drivers/usb/host/ohci-pci.c

···
 		ohci_dbg(ohci, "enabled AMD prefetch quirk\n");
 	}
 
+	ohci->flags |= OHCI_QUIRK_GLOBAL_SUSPEND;
 	return 0;
 }
 

drivers/usb/host/ohci.h

···
 #define	OHCI_QUIRK_HUB_POWER	0x100			/* distrust firmware power/oc setup */
 #define	OHCI_QUIRK_AMD_PLL	0x200			/* AMD PLL quirk*/
 #define	OHCI_QUIRK_AMD_PREFETCH	0x400			/* pre-fetch for ISO transfer */
+#define	OHCI_QUIRK_GLOBAL_SUSPEND	0x800		/* must suspend ports */
+
 	// there are also chip quirks/bugs in init logic
 
 	struct work_struct	nec_work;	/* Worker for NEC quirk */