Re: [PATCH 02/10] usb: musb: Fix idling after host mode by increasing autosuspend delay

[Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>]

Hi,

On Thu, May 05, 2016 at 10:04:39AM -0700, Tony Lindgren wrote:
> * Bin Liu <b-liu-l0cyMroinI0@public.gmane.org> [160505 08:04]:
> > Hi,
> > 
> > On Thu, Apr 28, 2016 at 10:33:12AM -0700, Tony Lindgren wrote:
> > > Looks like at least 2430 glue won't idle reliably with the 200 ms
> > > autosuspend delay. This causes deeper idle states being blocked for
> > > the whole SoC when disconnecting OTG A cable.
> > > 
> > > Increasing the delay to 500 ms seems to idle both MUSB and the PHY
> > > reliably. This is probably because of time needed by the hardware
> > > based negotiation between MUSB and the PHY.
> > 
> > Unless we know other glues also have the same issue, this change
> > affects other glues, right? Can we just increase it for 2430 only?
> 
> Well it's hard to say with no PM working with other glue layers right
> now. I would not be suprised if similar issue exists with other phys

Right.

> too talking with musb.
> 
> Does the current 200 ms autosuspend timeout relate to anything real
> other than what I found out with my measurements?

Not sure, I didn't checkk where the 200ms comes from.

> 
> If there's no other data available for the 200 ms timeout, I suggest
> we just set it to 500 ms and add comments there that at least 2430
> glue needs that. If things are not idling properly for the whole
> SoC because musb, the power consumption will be way worse than any
> power savings between 200 and 500 ms :)

Yeah, make sense.

> 
> BTW, I noticed 300 ms did not make a difference there, and 500 ms
> seems to work so far.
> 
> Regards,
> 
> Tony

Regards,
-Bin.

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