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From: Shawn Guo <shawnguo@kernel.org>
To: Kohji Okuno <okuno.kohji@jp.panasonic.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	linux-arm-kernel@lists.infradead.org,
	NXP Linux Team <linux-imx@nxp.com>
Subject: Re: [PATCH v3] ARM: imx6q: cpuidle: fix bug that CPU might not wake up at expected time
Date: Mon, 4 Mar 2019 15:06:58 +0800	[thread overview]
Message-ID: <20190304070656.GF26041@dragon> (raw)
In-Reply-To: <20190226023413.19531-1-okuno.kohji@jp.panasonic.com>

On Tue, Feb 26, 2019 at 11:34:13AM +0900, Kohji Okuno wrote:
>  In the current cpuidle implementation for i.MX6q, the CPU that sets
> 'WAIT_UNCLOCKED' and the CPU that returns to 'WAIT_CLOCKED' are always
> the same. While the CPU that sets 'WAIT_UNCLOCKED' is in IDLE state of
> "WAIT", if the other CPU wakes up and enters IDLE state of "WFI"
> istead of "WAIT", this CPU can not wake up at expired time.
>  Because, in the case of "WFI", the CPU must be waked up by the local
> timer interrupt. But, while 'WAIT_UNCLOCKED' is set, the local timer
> is stopped, when all CPUs execute "wfi" instruction. As a result, the
> local timer interrupt is not fired.
>  In this situation, this CPU will wake up by IRQ different from local
> timer. (e.g. broacast tiemr)

s/tiemr/timer

> 
> So, this fix changes CPU to return to 'WAIT_CLOCKED'.
> 
> Signed-off-by: Kohji Okuno <okuno.kohji@jp.panasonic.com>

Applied the patch with following Fixes tag.

Fixes: e5f9dec8ff5f ("ARM: imx6q: support WAIT mode using cpuidle")

Thanks for the fixing.

Shawn

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  parent reply	other threads:[~2019-03-04  7:08 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-22  8:49 [PATCH] ARM: imx6q: cpuidle: fix bug that CPU may not wake up Kohji Okuno
2019-02-22  9:14 ` Lucas Stach
2019-02-22 12:25   ` Fabio Estevam
2019-02-26  2:06 ` [PATCH v2] ARM: imx6q: cpuidle: fix bug that CPU might not wake up at expected time Kohji Okuno
2019-02-26  2:12   ` Fabio Estevam
2019-02-26  2:19     ` Kohji Okuno
2019-02-26  2:22       ` Fabio Estevam
2019-02-26  2:23       ` Kohji Okuno
2019-02-26  2:34 ` [PATCH v3] " Kohji Okuno
2019-03-01  9:23   ` Shawn Guo
2019-03-04  1:28     ` Kohji Okuno
2019-03-04  7:00       ` Shawn Guo
2019-03-04  7:06   ` Shawn Guo [this message]
2019-03-04  7:38     ` Kohji Okuno
2019-03-05 10:38     ` Kohji Okuno
2019-03-06  3:21       ` Shawn Guo
2019-03-06  4:30         ` [PATCH] ARM: imx6: cpuidle: omit the unnecessary unmask of GINT Kohji Okuno
2019-03-19 12:51           ` Shawn Guo
2019-03-20  0:07             ` Kohji Okuno
2019-03-20  1:12               ` Peng Fan
2019-03-20  3:08                 ` Aisheng Dong
2019-03-20  7:44                 ` Shawn Guo
2019-03-20  7:59                   ` Peng Fan
2019-03-20 14:28                     ` Shawn Guo
2019-03-20 14:35           ` Shawn Guo
2019-03-06 14:36       ` [PATCH v3] ARM: imx6q: cpuidle: fix bug that CPU might not wake up at expected time Peng Fan
2019-03-07  0:06         ` Kohji Okuno

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