Re: [3.16.1 BISECTED REGRESSION]: Simtec Entropy Key (cdc-acm) broken in 3.16

[Nix <nix@esperi.org.uk>]

On 6 Nov 2014, Johan Hovold said:

> On Thu, Nov 06, 2014 at 01:49:13PM +0000, Nix wrote:
>> On 5 Nov 2014, Johan Hovold told this:
>> > On Wed, Nov 05, 2014 at 03:14:49PM +0000, Nix wrote:
>
>> > Could you try two more things (too make sure line control is really the
>> > culprit):
>> >
>> > 1. If you clear HUPCL in ekeyd so that the lines are never lowered, does
>> > that fix the stability issue?
>> 
>> Definitely not. I got a hang after the first reboot out of an afflicted
>> kernel, when using a HUPCLless ekeyd. Weird. (I guess they're lowered on
>> reboot anyway?)
>
> It's actually only the timings related to the control-lines being raised
> on open that has changed, so this would seem consistent with that.

Urgh. No wonder it was intermittent.

> Thanks for tracking this down. That bisect cannot have been fun given
> the low failure rate (sometimes only one in ten reboots?).

It often failed quite fast, but yes, the negative case was hard to
prove: I had to rewind twice. I counted reboots because I'm a flaming
aspie pedant. 173 reboots that took... thank goodness it replicated on
the machine of mine that's fastest to reboot!

-- 
NULL && (void)