> > Due to that, I've moved the call to a workqueue instance.
>
> You can avoid using a workqueue by calling usb_hcd_poll_rh_status() at the
> end of ehci_irq(), after the spinlock has been released. Doing an extra
> test of the STS_PCD bit is a lot less overhead than starting up a
> workqueue.
>
> Also, you don't need to clear hcd->poll_rh in the hub_status routine.
> The core never touches that flag, so it won't get set unless ehci-hcd sets
> it.
>
> > Insertion/removal of cards works as expected, but I'm afraid that there
> > are corner cases which this simplistic code is not handling?
> >
> > Is it necessary to poll status during certain situations?
>
> Not as far as I know. Something may turn up in the future.
>
> One thing to watch out for is that some controllers might use
> "level-triggered" rather than "edge-triggered" interrupt reporting, even
> though the spec says they shouldn't. For such controllers it would be
> necessary to disable the STS_PCD bit when an interrupt occurs and not
> re-enable it until hcd->hub_irq_enable() is called. However I don't know
> whether any existing controllers include this design mistake.
How about this, then:
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 025d333..5c90bde 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -496,6 +496,9 @@ static int ehci_run (struct usb_hcd *hcd
u32 temp;
u32 hcc_params;
+ hcd->uses_new_polling = 1;
+ hcd->poll_rh = 0;
+
/* EHCI spec section 4.1 */
if ((retval = ehci_reset(ehci)) != 0) {
ehci_mem_cleanup(ehci);
@@ -661,6 +664,8 @@ dead:
if (bh)
ehci_work (ehci);
spin_unlock (&ehci->lock);
+ if (status & STS_PCD)
+ usb_hcd_poll_rh_status(hcd);
return IRQ_HANDLED;
}
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