USB: OHCI: disable RHSC inside interrupt handler

This patch (as808b) moves the Root Hub Status Change interrupt-disable
code in ohci-hcd back into the interrupt handler proper, to avoid the
chance of adverse interactions with mediocre hardware implementations.

It also deletes the root-hub status timer from within the interrupt-enable
routine.  There's no need to poll for status any more once interrupts are
re-enabled.

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

2 files changed, 18 insertions, 16 deletions

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index ea4714e557e4..a95275a401b1 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -729,6 +729,16 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
                 ohci->next_statechange = jiffies + STATECHANGE_DELAY;
                 ohci_writel(ohci, OHCI_INTR_RD | OHCI_INTR_RHSC,
                                 &regs->intrstatus);
+
+                /* NOTE: Vendors didn't always make the same implementation
+                 * choices for RHSC.  Many followed the spec; RHSC triggers
+                 * on an edge, like setting and maybe clearing a port status
+                 * change bit.  With others it's level-triggered, active
+                 * until khubd clears all the port status change bits.  We'll
+                 * always disable it here and rely on polling until khubd
+                 * re-enables it.
+                 */
+                ohci_writel(ohci, OHCI_INTR_RHSC, &regs->intrdisable);
                 usb_hcd_poll_rh_status(hcd);
         }
 
diff --git a/drivers/usb/host/ohci-hub.c b/drivers/usb/host/ohci-hub.c
index 99357b99d133..1e5ed3bb1a93 100644
--- a/drivers/usb/host/ohci-hub.c
+++ b/drivers/usb/host/ohci-hub.c
@@ -41,7 +41,11 @@ static void ohci_rhsc_enable (struct usb_hcd *hcd)
 {
         struct ohci_hcd         *ohci = hcd_to_ohci (hcd);
 
-        ohci_writel (ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
+        spin_lock_irq(&ohci->lock);
+        if (!ohci->autostop)
+                del_timer(&hcd->rh_timer);      /* Prevent next poll */
+        ohci_writel(ohci, OHCI_INTR_RHSC, &ohci->regs->intrenable);
+        spin_unlock_irq(&ohci->lock);
 }
 
 #define OHCI_SCHED_ENABLES \
@@ -348,7 +352,7 @@ ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
 {
         struct ohci_hcd *ohci = hcd_to_ohci (hcd);
         int             i, changed = 0, length = 1;
-        int             any_connected = 0, rhsc_enabled = 1;
+        int             any_connected = 0;
         unsigned long   flags;
 
         spin_lock_irqsave (&ohci->lock, flags);
@@ -389,19 +393,6 @@ ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
                 }
         }
 
-        /* NOTE:  vendors didn't always make the same implementation
-         * choices for RHSC.  Sometimes it triggers on an edge (like
-         * setting and maybe clearing a port status change bit); and
-         * it's level-triggered on other silicon, active until khubd
-         * clears all active port status change bits.  If it's still
-         * set (level-triggered) we must disable it and rely on
-         * polling until khubd re-enables it.
-         */
-        if (ohci_readl (ohci, &ohci->regs->intrstatus) & OHCI_INTR_RHSC) {
-                ohci_writel (ohci, OHCI_INTR_RHSC, &ohci->regs->intrdisable);
-                (void) ohci_readl (ohci, &ohci->regs->intrdisable);
-                rhsc_enabled = 0;
-        }
         hcd->poll_rh = 1;
 
         /* carry out appropriate state changes */
@@ -412,7 +403,8 @@ ohci_hub_status_data (struct usb_hcd *hcd, char *buf)
                  * and RHSC is enabled */
                 if (!ohci->autostop) {
                         if (any_connected) {
-                                if (rhsc_enabled)
+                                if (ohci_readl(ohci, &ohci->regs->intrenable) &
+                                                OHCI_INTR_RHSC)
                                         hcd->poll_rh = 0;
                         } else {
                                 ohci->autostop = 1;