usb: Remove broken optimisation in OHCI IRQ handler

[karo-tx-linux.git] / drivers / usb / host / ohci-hcd.c

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 704f33fdd2f12bc974966568984c2d63baf4c7a4..ecfe800fd7208e6c9602e87d51affcb4d2f948be 100644 (file)
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -732,24 +732,27 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
        struct ohci_regs __iomem *regs = ohci->regs;
        int                     ints;
 
-       /* we can eliminate a (slow) ohci_readl()
-        * if _only_ WDH caused this irq
+       /* Read interrupt status (and flush pending writes).  We ignore the
+        * optimization of checking the LSB of hcca->done_head; it doesn't
+        * work on all systems (edge triggering for OHCI can be a factor).
         */
-       if ((ohci->hcca->done_head != 0)
-                       && ! (hc32_to_cpup (ohci, &ohci->hcca->done_head)
-                               & 0x01)) {
-               ints =  OHCI_INTR_WDH;
+       ints = ohci_readl(ohci, &regs->intrstatus);
 
-       /* cardbus/... hardware gone before remove() */
-       } else if ((ints = ohci_readl (ohci, &regs->intrstatus)) == ~(u32)0) {
+       /* Check for an all 1's result which is a typical consequence
+        * of dead, unclocked, or unplugged (CardBus...) devices
+        */
+       if (ints == ~(u32)0) {
                disable (ohci);
                ohci_dbg (ohci, "device removed!\n");
                return IRQ_HANDLED;
+       }
+
+       /* We only care about interrupts that are enabled */
+       ints &= ohci_readl(ohci, &regs->intrenable);
 
        /* interrupt for some other device? */
-       } else if ((ints &= ohci_readl (ohci, &regs->intrenable)) == 0) {
+       if (ints == 0)
                return IRQ_NOTMINE;
-       }
 
        if (ints & OHCI_INTR_UE) {
                // e.g. due to PCI Master/Target Abort