[BUG] mach-msm/msm_vibrator.c - very long vibration if CPU suspends

[BUG] mach-msm/msm_vibrator.c - very long vibration if CPU suspends

[abhilash jindal]

msm_vibrator.c uses hrtimer to switch off the phone vibration as follows-

hrtimer_start(&vibe_timer, ktime_set(value / 1000, (value % 1000) *
1000000), HRTIMER_MODE_REL);

However, hrtimer does not get fired after the CPU suspends. Hence, if
the CPU suspends before the timer gets fired, the phone continues
vibrating until the next time when CPU wakes up causing unnecessary
battery drain (which can be as long as 15 minutes).

IMHO, one way to fix it would be to replace hrtimer by android alarm timer.

Thanks
Abhilash Jindal

Re: [BUG] mach-msm/msm_vibrator.c - very long vibration if CPU suspends

[David Brown]

On Wed, Sep 04, 2013 at 05:24:50PM -0400, abhilash jindal wrote:
>msm_vibrator.c uses hrtimer to switch off the phone vibration as follows-
>
>hrtimer_start(&vibe_timer, ktime_set(value / 1000, (value % 1000) *
>1000000), HRTIMER_MODE_REL);
>
>However, hrtimer does not get fired after the CPU suspends. Hence, if
>the CPU suspends before the timer gets fired, the phone continues
>vibrating until the next time when CPU wakes up causing unnecessary
>battery drain (which can be as long as 15 minutes).
>
>IMHO, one way to fix it would be to replace hrtimer by android alarm timer.

It looks like this file exists only in the codeaurora.org MSM tree,
and not in the mainline kernel.  The first thing I'd mention is that
if you are an MSM customer, you'll be much better off reporting this
through the customer support chain.

Otherwise, I can forward this information internally.  I'm not sure if
they'll be any response, since it doesn't appear to be used in any
recent targets.

David

-- 
sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Re: [BUG] mach-msm/msm_vibrator.c - very long vibration if CPU suspends

[abhilash jindal]

Thanks for the reply ! I reported it here because the bug is present
in the main android tree:

https://android.googlesource.com/kernel/msm.git/+/android-msm-2.6.35/arch/arm/mach-msm/msm_vibrator.c

abhilash

On Wed, Sep 11, 2013 at 3:47 PM, David Brown <davidb@codeaurora.org> wrote:
> On Wed, Sep 04, 2013 at 05:24:50PM -0400, abhilash jindal wrote:
>>
>> msm_vibrator.c uses hrtimer to switch off the phone vibration as follows-
>>
>> hrtimer_start(&vibe_timer, ktime_set(value / 1000, (value % 1000) *
>> 1000000), HRTIMER_MODE_REL);
>>
>> However, hrtimer does not get fired after the CPU suspends. Hence, if
>> the CPU suspends before the timer gets fired, the phone continues
>> vibrating until the next time when CPU wakes up causing unnecessary
>> battery drain (which can be as long as 15 minutes).
>>
>> IMHO, one way to fix it would be to replace hrtimer by android alarm
>> timer.
>
>
> It looks like this file exists only in the codeaurora.org MSM tree,
> and not in the mainline kernel.  The first thing I'd mention is that
> if you are an MSM customer, you'll be much better off reporting this
> through the customer support chain.
>
> Otherwise, I can forward this information internally.  I'm not sure if
> they'll be any response, since it doesn't appear to be used in any
> recent targets.
>
> David
>
> --
> sent by an employee of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation