Bjørn Mork <bjorn@mork.no> writes:
> Alan Stern <stern@rowland.harvard.edu> writes:
>> On Mon, 16 Jun 2014, Bjørn Mork wrote:
>>> Bjørn Mork <bjorn@mork.no> writes:
>>> 
>>> > So the problem is related to runtime suspend before first use. I
>>> > strongly suspect 
>>> >
>>> >  aae4518b3124 PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily
>>> 
>>> Nope, that was not it. So if blind guessing isn't going to work, then I
>>> guess there is no way around a bisect :-)
>>
>> You could simply wait for someone who knows the code to answer the 
>> question.  :-)
>
> Wait? Do I look like I'm patient :-)
>
> Besides, it was actually relieving to bisect a reliably reproducible
> non-crashing bug for once ;-)
>
>> I'm pretty sure this resulted from one of Dan Williams's changes to USB 
>> port runtime PM.  A whole bunch of them were added in 3.15-rc1.
>
> You are *so* much better at guessing than me:
>
> 9262c19d14c433a6a1ba25c3ff897cb89e412309 is the first bad commit

And for completeness, I just tried the following partial revert on top
of v3.16-rc1 and can confirm that it works fine for me: