From: Kohji Okuno <okuno.kohji@jp.panasonic.com>
To: <shawnguo@kernel.org>
Cc: s.hauer@pengutronix.de, okuno.kohji@jp.panasonic.com,
linux-imx@nxp.com, kernel@pengutronix.de, fabio.estevam@nxp.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3] ARM: imx6q: cpuidle: fix bug that CPU might not wake up at expected time
Date: Tue, 5 Mar 2019 19:38:05 +0900 [thread overview]
Message-ID: <20190305.193805.2098843820562835621.okuno.kohji@jp.panasonic.com> (raw)
In-Reply-To: <20190304070656.GF26041@dragon>
Hi Shawn,
I found the fix of the same issue on linux-imx repository. Could you
refer to the following?
https://source.codeaurora.org/external/imx/linux-imx/commit/?h=imx_4.1.y_brillo&id=f739483488ef76979c06efea397237756bec45b9
Regarding the fix of cpuidle-imx6q.c, my fix is better, I think.
But, we may also need to modify pm-imx6.c.
# I cannot understand why they doesn't release their modifications.
Best regards,
Kohji Okuno
Shawn Guo <shawnguo@kernel.org> wrote:
> 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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next prev parent reply other threads:[~2019-03-05 10:38 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
2019-03-04 7:38 ` Kohji Okuno
2019-03-05 10:38 ` Kohji Okuno [this message]
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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