Re: [PATCH 5/6] USB: Support wakeup IRQ for suspended controllers

Roger Quadros
2013-07-11T07:30:07Z

On 07/10/2013 09:45 PM, Alan Stern wrote:
> On Wed, 10 Jul 2013, Roger Quadros wrote:
>
>> Some platforms e.g. ehci-omap can generate an interrupt
>> (i.e. remote wakeup) even when the controller is suspended i.e.
>> HW_ACCESSIBLE is cleared.
>>
>> Introduce a flag "has_wakeup_irq" in struct usb_hcd to indicate
>> such cases.
>>
>> We tackle this case by disabling the IRQ, scheduling a
>> hub resume and enabling back the IRQ after the controller has
>> resumed. This ensures that the IRQ handler runs only after the
>> controller is accessible.
>
>> @@ -2248,7 +2253,21 @@ irqreturn_t usb_hcd_irq (int irq, void *__hcd)
>> */
>> local_irq_save(flags);
>>
>> - if (unlikely(HCD_DEAD(hcd) || !HCD_HW_ACCESSIBLE(hcd)))
>> + if (unlikely(HCD_DEAD(hcd)))
>> + rc = IRQ_NONE;
>> + else if (unlikely(!HCD_HW_ACCESSIBLE(hcd) && hcd->has_wakeup_irq)) {
>> + /*
>> + * We got a wakeup interrupt while the controller was
>> + * suspending or suspended. We can't handle it now, so
>> + * disable the IRQ and resume the root hub (and hence
>> + * the controller too).
>> + */
>> + disable_irq_nosync(hcd->irq);
>> + set_bit(HCD_FLAG_IRQ_DISABLED, &hcd->flags);
>> + usb_hcd_resume_root_hub(hcd);
>> +
>> + rc = IRQ_HANDLED;
>> + } else if (unlikely(!HCD_HW_ACCESSIBLE(hcd)))
>> rc = IRQ_NONE;
>
> In the interest of minimizing the amount of work needed in the most
> common case, this should be written as:
>
> else if (unlikely(!HCD_HW_ACCESSIBLE(hcd))) {
> if (hcd->has_wakeup_irq) {
> ...
> } else
> rc = IRQ_NONE;
>

OK.

>> else if (hcd->driver->irq(hcd) == IRQ_NONE)
>> rc = IRQ_NONE;
>
> Apart from that, the patch is okay. When you rearrange the logic, you
> can add my Acked-by.
>
Thanks.

cheers,
-roger