Re: [PATCH 00/16] OMAP USB Host cleanup

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On Tue, Nov 27, 2012 at 04:42:47PM +0200, Roger Quadros wrote:
> On 11/20/2012 01:22 AM, Kevin Hilman wrote:
> > Roger Quadros <rogerq@xxxxxx> writes:
> > 
> >> Kevin,
> >>
> >> On 11/16/2012 10:08 PM, Kevin Hilman wrote:
> >>> Roger Quadros <rogerq@xxxxxx> writes:
> >>>
> >>>> Hi,
> >>>>
> >>>> This patchset addresses the following
> >>>>
> >>>> - Avoid addressing clocks one by one by name and use a for loop + bunch
> >>>>   of cleanups.
> >>>> - Get number of channels/ports dynamically either from revision register
> >>>>   or from platform data. Avoids getting clocks that are not present.
> >>>> - Add OMAP5 and HSIC mode (Not tested)
> >>>> - Save power on Panda when EHCI driver is not loaded.
> >>>>
> >>>
> >>> Seeing the clock changes/cleanups, I gave this a spin on OMAP3
> >>> (3530/Beagle, 3530/Overo, 3730/Beagle-xM, 3730/OveroSTORM) to see if it
> >>> fixed up the problem where CORE does not hit retention in idle when USB
> >>> host is enabled, even with no devices attached.
> >>>
> >>> Unfortunately, it didn't help. :(
> >>
> >> oh that's bad. But this series wasn't meant to fix that ;).
> > 
> > Oh, sorry.  Yeah, I didn't mean this as a nak.  Just an opportunity to
> > complain to the maintainers that a long-standing issue needs to be
> > addressed.
> > 
> 
> Kevin,
> 
> I gave a quick look at the issue. It seems that the High Speed USB Host
> module is kept in Software forced wakeup mode as a quick fix workaround
> to a bunch of silicon erratas. And we do nothing on USB global suspend.
> That's why CORE does not hit retention.
> 
> If we runtime_suspend the USB host module on USB global suspend then it
> will be put in Force Idle mode. This will allow CORE to hit retention
> but then we will no longer be able to detect USB device connect events.
> 
> So, till we have a better solution I will suggest to keep EHCI_HCD as a
> module in omap2plus_defconfig.

I guess that "better solution" would be I/O pads wakeup interrupts ? But
I don't think that's already in mainline, is it ?

-- 
balbi

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