Re: xHCI problem? [was Re: Erratic USB device behavior and device loss]

Ritesh Raj Sarraf
2016-09-09T13:14:21Z

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On Fri, 2016-09-09 at 12:54 +0200, Ulf Hansson wrote:
> This affects the way the core calls the host driver's ->set_ios()
> callback. Earlier it was invoked first to do power off then power up.
> With this change it starts with power up instead.
> I wanted to try this because I suspected the initial state could be wrong.
>
> So here are some other ideas on how to move forward.
> 1. Run with CONFIG_PM unset to see if we can reproduce the problem.
> 2. Revert back the state in the mmc core we had in 3.16 around how it
> deals with runtime PM for host devices. That's actually very easy as
> we only need to remove the pm_runtime_put|get() calls in
> mmc_claim|release_host().
>
> Ritesh, can you try these options?
>

Yes. I can try the above ones now. I'm building the kernel for it.

> Neither of the above will actually solve the problem, so I guess we
> anyway need take a closer look to understand why the usb device is
> accessed when it is actually runtime suspended.
>
> BTW, Ritesh you could also run a git bisect to find out if/when this
> became broken.

What starting point do you want me to use ? 4.0 ?

- --
Ritesh Raj Sarraf
RESEARCHUT - http://www.researchut.com
"Necessity is the mother of invention."
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