Re: Changes to power management in ehci-tegra

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On Thu, 19 Apr 2012, Stephen Warren wrote:

> > If you make that change, does the driver continue to work as well as it 
> > did before?
> 
> Yes, I believe so.
> 
> Note: I found that the immediate resume is because hcd_bus_suspend()
> aborts part-way through due to "suspend raced with wakeup event", which
> is due to ehci_hub_status_data() finding that port_status has all of
> PORT_CSC | PORT_PEC | PORT_OCC set. Is it worth tracking that down
> further? I have no idea if it's an ehci-tegra.c issue or quirk in our
> EHCI HW.

It's probably because of the recent change to hcd_bus_suspend().  
Before that change, it did not call ehci_hub_status_data() after doing
the suspend.  But now you see the problem: ehci_hub_status_data()  
returns bogus information because the controller has been powered down.  
That's the reason why I wanted to update ehci-tegra.c.

If you revert commit 879d38e6bc36d73b0ac40ec9b0d839fda9fa8b1a, how well
does the current driver behave?

Alan Stern

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