On Fri, Aug 12, 2011 at 16:30, Todd Poynor [off-list ref] wrote:

On Fri, Aug 12, 2011 at 12:20:21PM +0530, Munegowda, Keshava wrote:

quoted

On Wed, Aug 10, 2011 at 10:01 PM, Todd Poynor [off-list ref] wrote:

quoted

quoted

@@ -913,12 +598,15 @@ static int usbhs_enable(struct device *dev)

                              (pdata->ehci_data->reset_gpio_port[1], 1);
      }

-end_count:
-     omap->count++;
+     pm_runtime_put_sync(dev);
      spin_unlock_irqrestore(&omap->lock, flags);

Is pm_runtime_irq_safe() needed (else I think runtime PM callbacks may
re-enable IRQs... or there's the new *_suspend runtime PM calls that
may avoid this)?

 pm_runtime_irq_safe()  is not required; usbhs does not have a parent
and it is the parent driver of
ehci and ohci drivers.

But the above expects IRQs to be disabled during the
pm_runtime_put_sync, and synchronous calls can turn IRQs back on in
rpm_idle:

       if (callback) {
               spin_unlock_irq(&dev->power.lock);

               callback(dev);

I see other folks who know this better than me are discussing USB run
time PM and might_sleep contexts, so I'll note this concern and let
others chime in if they think there's a real problem here.

It is rather easy with the following patch applied to pull this bug out!
https://patchwork.kernel.org/patch/1001572/

Regards,
Nishanth Menon
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