Re: [patch 61/66] timers: Convert to hotplug state machine

From: Jon Hunter
Date: Tue Jul 26 2016 - 14:21:12 EST

Hi Thomas,

On 26/07/16 15:15, Thomas Gleixner wrote:
> Jon,
> On Tue, 26 Jul 2016, Jon Hunter wrote:
>> On 25/07/16 16:35, rcochran@xxxxxxxxxxxxx wrote:
>>> Just to be sure, this problem didn't exist before the HP rework, that
>>> is, suspend worked fine with and without CONFIG_PREEMPT, right?
>> Correct. I test suspend on Tegra with both multi_v7_defconfig
>> (CONFIG_PREEMPT disabled) and tegra_defconfig (CONFIG_PREEMPT enabled).
>> Looking at the git history for these configs I don't see any changes in
>> this regard since they were added (unless some underlying Kconfig files
>> have changed).
> Is that fully reproducible, i.e on every suspend?

No not every suspend. I run 10 suspend cycles on each Tegra board (5
boards total) and typically between 3 and 5 boards would see the stall
in the 10 suspend cycles. So it does appear to be timing sensitive.

> Can you please check whether this issue happens with just cpu offline as
> well? I.e. set a cpu (or all non-boot cpus) offline, wait long enough that the
> stall detector can trigger, set the cpu(s) online again and repeat.

I can, but it appears like Richard's patch has fixed this. I am happy to
do more testing if necessary.