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From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arch_timer: Move delay timer to drivers clocksource
Date: Fri, 17 Jan 2014 10:36:33 -0800	[thread overview]
Message-ID: <52D97831.6030700@codeaurora.org> (raw)
In-Reply-To: <52D932B5.7020909@nvidia.com>

On 01/17/14 05:40, Prashant Gaikwad wrote:
>
> Another requirement:
>
> We have 3 timers T1, T2, T3 used as wake events for 3 idle states C1,
> C2, C3 respectively.
>
> Rating of T2 is better than T3. If I register T2 and T3 both as
> broadcast timers then T3 will not be used. But ...
>     - T2 is not preserved in C3 idle state.
>     - T3 resolution is very poor (ms) and can not be used as wake
> event for C2.
>
> Possible solution, register only T3 as broadcast device and use T2 as
> per-CPU fallback timer.

We have the same situation on MSM. I've been thinking about proposing we
allow multiple broadcast timers to exist in the system and then have the
clockevents_notify() caller indicate which C state is being entered. The
broadcast timers would need to indicate which C state they don't work in
though.

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

  reply	other threads:[~2014-01-17 18:36 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-15 13:07 [PATCH] arch_timer: Move delay timer to drivers clocksource Prashant Gaikwad
2014-01-15 15:41 ` Rob Herring
2014-01-16  4:45   ` Prashant Gaikwad
2014-01-15 15:45 ` Will Deacon
2014-01-16  5:19   ` Prashant Gaikwad
2014-01-16 12:16     ` Will Deacon
2014-01-17  9:07       ` Antti Miettinen
2014-01-17  9:12         ` Daniel Lezcano
2014-01-17 10:11           ` Prashant Gaikwad
2014-01-17 10:15             ` Daniel Lezcano
2014-01-17 11:37               ` Prashant Gaikwad
2014-01-17 12:08                 ` Daniel Lezcano
2014-01-17 13:40                   ` Prashant Gaikwad
2014-01-17 18:36                     ` Stephen Boyd [this message]
2014-01-20 14:42                       ` Daniel Lezcano
2014-01-20 14:56                         ` Lorenzo Pieralisi
2014-01-20 15:28                           ` Daniel Lezcano
2014-01-21  8:20                         ` Prashant Gaikwad
2014-01-21  8:40                           ` Daniel Lezcano
2014-01-21  8:53                             ` Prashant Gaikwad
2014-01-19  5:20                     ` Antti Miettinen
2014-01-20 14:41                     ` Daniel Lezcano
2014-01-21  8:10                       ` Prashant Gaikwad
2014-01-21  8:25                         ` Daniel Lezcano
2014-01-17 10:30           ` Antti Miettinen

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