linux-kernel - Re: Regression in v5.0-rc1 with autosuspend hrtimers

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Message-ID: <20190108213743.GN5544@atomide.com>
Date:   Tue, 8 Jan 2019 13:37:43 -0800
From:   Tony Lindgren <tony@...mide.com>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "open list:THERMAL" <linux-pm@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        LAK <linux-arm-kernel@...ts.infradead.org>,
        linux-omap@...r.kernel.org
Subject: Re: Regression in v5.0-rc1 with autosuspend hrtimers

* Vincent Guittot <vincent.guittot@...aro.org> [190108 16:42]:
> On Tue, 8 Jan 2019 at 16:53, Tony Lindgren <tony@...mide.com> wrote:
> > Hmm so could it be that we now rely on timers that that may
> > not be capable of waking up the system from idle states with
> > hrtimer?
> 
> With nohz and hrtimer enabled,  timer relies on hrtimer to generate
> the tick so you should use the same interrupt.

OK yeah looks like that part is working just fine.

Adding some printks and debugging over ssh, looks like
omap8250_runtime_resume() gets called just fine based on a wakeirq,
but then omap8250_runtime_suspend() runs immediately instead of
waiting for the three second timeout.

Lowering the autosuspend_delay_ms to 2100 ms makes things work again.
Anything higher than 2200 ms seems to somehow time out immediately
now :)

Regards,

Tony