[PATCH] ARM: tegra: cpuidle: use CPUIDLE_FLAG_TIMER_STOP flag

Daniel Lezcano daniel.lezcano at linaro.org
Wed Jul 17 06:21:18 EDT 2013

On 07/17/2013 12:15 PM, Joseph Lo wrote:
> On Wed, 2013-07-17 at 03:51 +0800, Stephen Warren wrote:
>> On 07/16/2013 05:17 AM, Joseph Lo wrote:
>>> On Tue, 2013-07-16 at 02:04 +0800, Stephen Warren wrote:
>>>> On 06/25/2013 03:23 AM, Joseph Lo wrote:
>>>>> Use the CPUIDLE_FLAG_TIMER_STOP and let the cpuidle framework
>>>>> to handle the CLOCK_EVT_NOTIFY_BROADCAST_ENTER/EXIT when entering
>>>>> this state.
>>> or something can increase
>>> the loading or make regressions. But I think you are testing with USB
>>> device attached, right? That might cause some extra loading. You can
>>> give it a try after just removing USB device. And I double confirm that
>>> on Seaboard. Except that, the test result looks OK for me.
>> Yes, having a USB device plugged in does affect the issue. In summary:
>> next-20130716, with or without USB devices plugged in: Works fine.
>> next-20130716 with your patches, without USB device plugged in:
>> Occasional short problems (detailed below).
>> next-20130716 with your patches, with USB device plugged in: Continual
>> long problems (detailed below).
>> The testing I did was to log in over the serial console, hit <enter>
>> around five times, and watch the shell prompt echo back, then type
>> "ls<enter" and watch the (directory listing appear (I have about 20
>> files in my directory, with long-ish names), then repeat. With plain
>> next-20130716, this is nice and fast and there are no pauses. With your
>> patches applied, there are occasional or continual pauses, which last
>> for either a short time (tenths of a second), or even a second or two,
>> both depending on whether a USB device is plugged in or not.
>> I believe this is the same issue I saw when I applied your patches to
>> the Tegra tree on top of v3.11-rc1.
> OK. I did more stress tests last night and today. I found it cause by
> the patch "ARM: tegra: cpuidle: use CPUIDLE_FLAG_TIMER_STOP flag" and
> only impact the Tegra20 platform. The hot plug regression seems due to
> this patch. After dropping this patch on top of v3.11-rc1, the Tegra20
> can back to normal.
> And the hop plug and suspend stress test can pass on Tegra30/114 too.
> Can the other two patch series for Tegra114 to support CPU idle power
> down mode and system suspend still moving forward, not be blocked by
> this patch?
> Looks the CPUIDLE_FLAG_TIMER_STOP flag still cause some other issue for
> hot plug on Tegra20, I will continue to check this. You can just drop
> this patch.

Please in the future Cc me when problems occur with some patches I
submitted. That would be easier for me to track the issues and fix them
when they happen.

  -- Daniel

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