[PATCH] USB: UHCI: don't track suspended ports

Someone recently posted a bug report where it turned out that uhci-hcd
was disagreeing with the UHCI controller over whether or not a port was
suspended: The driver thought it wasn't and the hardware thought it was.
This patch (as665) fixes the problem and simplifies the driver by
removing the internal state-tracking completely.  Now the driver just
asks the hardware whether a port is suspended.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/uhci-hcd.c

@@ -115,8 +115,7 @@ static void finish_reset(struct uhci_hcd *uhci)
 	for (port = 0; port < uhci->rh_numports; ++port)
 		outw(0, uhci->io_addr + USBPORTSC1 + (port * 2));
 
-	uhci->port_c_suspend = uhci->suspended_ports =
-			uhci->resuming_ports = 0;
+	uhci->port_c_suspend = uhci->resuming_ports = 0;
 	uhci->rh_state = UHCI_RH_RESET;
 	uhci->is_stopped = UHCI_IS_STOPPED;
 	uhci_to_hcd(uhci)->state = HC_STATE_HALT;

drivers/usb/host/uhci-hcd.h

@@ -415,7 +415,6 @@ struct uhci_hcd {
 
 	/* Support for port suspend/resume/reset */
 	unsigned long port_c_suspend;		/* Bit-arrays of ports */
-	unsigned long suspended_ports;
 	unsigned long resuming_ports;
 	unsigned long ports_timeout;		/* Time to stop signalling */
 

drivers/usb/host/uhci-hub.c

@@ -85,18 +85,18 @@ static void uhci_finish_suspend(struct uhci_hcd *uhci, int port,
 {
 	int status;
 
-	if (test_bit(port, &uhci->suspended_ports)) {
+	if (inw(port_addr) & (USBPORTSC_SUSP | USBPORTSC_RD)) {
 		CLR_RH_PORTSTAT(USBPORTSC_SUSP | USBPORTSC_RD);
-		clear_bit(port, &uhci->suspended_ports);
-		clear_bit(port, &uhci->resuming_ports);
-		set_bit(port, &uhci->port_c_suspend);
+		if (test_bit(port, &uhci->resuming_ports))
+			set_bit(port, &uhci->port_c_suspend);
 
 		/* The controller won't actually turn off the RD bit until
 		 * it has had a chance to send a low-speed EOP sequence,
 		 * which takes 3 bit times (= 2 microseconds).  We'll delay
 		 * slightly longer for good luck. */
 		udelay(4);
 	}
+	clear_bit(port, &uhci->resuming_ports);
 }
 
 /* Wait for the UHCI controller in HP's iLO2 server management chip.
@@ -265,8 +265,6 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 			wPortChange |= USB_PORT_STAT_C_SUSPEND;
 			lstatus |= 1;
 		}
-		if (test_bit(port, &uhci->suspended_ports))
-			lstatus |= 2;
 		if (test_bit(port, &uhci->resuming_ports))
 			lstatus |= 4;
 
@@ -309,7 +307,6 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 
 		switch (wValue) {
 		case USB_PORT_FEAT_SUSPEND:
-			set_bit(port, &uhci->suspended_ports);
 			SET_RH_PORTSTAT(USBPORTSC_SUSP);
 			OK(0);
 		case USB_PORT_FEAT_RESET:
@@ -343,8 +340,11 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 			CLR_RH_PORTSTAT(USBPORTSC_PEC);
 			OK(0);
 		case USB_PORT_FEAT_SUSPEND:
-			if (test_bit(port, &uhci->suspended_ports) &&
-					!test_and_set_bit(port,
+			if (!(inw(port_addr) & USBPORTSC_SUSP)) {
+
+				/* Make certain the port isn't suspended */
+				uhci_finish_suspend(uhci, port, port_addr);
+			} else if (!test_and_set_bit(port,
 						&uhci->resuming_ports)) {
 				SET_RH_PORTSTAT(USBPORTSC_RD);