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From: Lorenzo Pieralisi <>
To: "Rafael J. Wysocki" <>
Cc: Daniel Lezcano <>,
	"" <>,
	"" <>,
	Peter Zijlstra <>,
Subject: Re: [PATCH 0/2] drivers: cpuidle: minor suspend-to-idle fixes
Date: Fri, 27 Feb 2015 10:00:00 +0000	[thread overview]
Message-ID: <20150227100000.GA5975@red-moon> (raw)
In-Reply-To: <4425438.YlYNQyf1hp@vostro.rjw.lan>

[CC'ed Preeti]

On Thu, Feb 26, 2015 at 11:37:54PM +0000, Rafael J. Wysocki wrote:
> Me versions of the two $subject patches follow.

Thank you. I am testing them and I have run into the following issue.

Starting with:

3810631 ("PM / sleep: Re-implement suspend-to-idle handling")

the suspend-to-idle code path in the cpuidle_idle_call() bypasses
the CPUIDLE_FLAG_TIMER_STOP code path entirely. Now, on most of
the current ARM platforms, the deepest idle state loses the tick device
context, therefore this means that going to idle through
suspend-to-idle becomes a brute force way of nuking the tick,
unless I am missing something here.

I am experiencing hangs on resume from suspend-to-idle when the broadcast
timer is the broadast-hrtimer (ie there is no HW broadcast timer in the
platform) and the deepest idle states lose the tick device context (ie
they are CPUIDLE_FLAG_TIMER_STOP), I hope Preeti can help me test this on
Power, still chasing the issue.

I could not reproduce the issue with a HW broadcast timer device.

Platform has deepest idle states that allow CPUs shutdown where the
local tick device is gone on entry, I am trying to provide you with a
backtrace, I need time to debug.

The question I have: is it safe to bypass the CPUIDLE_FLAG_TIMER_STOP
and related broadcast mode entry/exit in the suspend-to-idle path ?

I do not think it is, but I am asking.

I can "force" tick freeze by initializing the enter_freeze pointer
in the idle states (that's the next thing I will test), but still, for
platforms where that's not possible my question above is still valid.


  parent reply	other threads:[~2015-02-27  9:59 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-24 17:58 Lorenzo Pieralisi
2015-02-24 17:58 ` [PATCH 1/2] drivers: cpuidle: remove stale irq disabling call in cpuidle_enter_freeze() Lorenzo Pieralisi
2015-02-25 14:13   ` Daniel Lezcano
2015-02-25 14:39     ` Lorenzo Pieralisi
2015-02-25 23:36       ` Rafael J. Wysocki
2015-02-26  9:48         ` Lorenzo Pieralisi
2015-02-26 16:39           ` Rafael J. Wysocki
2015-02-24 17:58 ` [PATCH 2/2] drivers: cpuidle: add driver/device checks " Lorenzo Pieralisi
2015-02-25 14:30   ` Daniel Lezcano
2015-02-25 14:47     ` Lorenzo Pieralisi
2015-02-25 23:50       ` Rafael J. Wysocki
2015-02-26  0:35         ` Rafael J. Wysocki
2015-02-25 14:56     ` Lorenzo Pieralisi
2015-02-26 23:37 ` [PATCH 0/2] drivers: cpuidle: minor suspend-to-idle fixes Rafael J. Wysocki
2015-02-26 23:39   ` [PATCH 1/2] idle / sleep: Avoid excessive interrupts disabling and enabling Rafael J. Wysocki
2015-02-26 23:39   ` [PATCH 2/2] cpuidle / sleep: Do sanity checks in cpuidle_enter_freeze() too Rafael J. Wysocki
2015-02-27  8:41   ` [PATCH 0/2] drivers: cpuidle: minor suspend-to-idle fixes Peter Zijlstra
2015-02-27 10:00   ` Lorenzo Pieralisi [this message]
2015-02-27 22:11     ` Rafael J. Wysocki
2015-02-28 11:54       ` Lorenzo Pieralisi
2015-02-28 23:58         ` Rafael J. Wysocki
2015-03-02 10:08           ` Lorenzo Pieralisi
2015-03-02 13:13             ` Rafael J. Wysocki
2015-03-02 14:50               ` [PATCH 0/2] cpuidle / sleep: fix timer stopping regression (was: drivers: cpuidle: minor suspend-to-idle fixes) Rafael J. Wysocki
2015-03-02 14:51                 ` [PATCH 1/2] cpuidle: Clean up fallback handling in cpuidle_idle_call() Rafael J. Wysocki
2015-03-02 16:05                   ` Lorenzo Pieralisi
2015-03-02 22:30                     ` Rafael J. Wysocki
2015-03-02 14:53                 ` [PATCH 2/2] cpuidle / sleep: Use broadcast timer for states that stop local timer Rafael J. Wysocki
2015-03-02 16:27                   ` Lorenzo Pieralisi
2015-03-02 22:28                     ` Rafael J. Wysocki

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