linux-kernel - Change behaviour when tracing ... nasty trap (was Re: [PATCH] PM/Trace: get rid of synchronous resume limit during PM trace)

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Message-ID: <20150126102352.GA1758@amd>
Date:	Mon, 26 Jan 2015 11:23:52 +0100
From:	Pavel Machek <pavel@....cz>
To:	"Fu, Zhonghui" <zhonghui.fu@...ux.intel.com>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>, len.brown@...el.com,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-pm@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	chuansheng.liu@...el.com
Subject: Change behaviour when tracing ... nasty trap (was Re: [PATCH]
 PM/Trace: get rid of synchronous resume limit during PM trace)

On Mon 2015-01-26 13:07:03, Fu, Zhonghui wrote:
> >From f9c841d1f943d81b5ab0aac7483e794a7f966296 Mon Sep 17 00:00:00 2001
> From: Zhonghui Fu <zhonghui.fu@...ux.intel.com>
> Date: Mon, 26 Jan 2015 11:27:08 +0800
> Subject: [PATCH] PM/Trace: get rid of synchronous resume limit during PM trace
> 
> There are some kind of dependency between devices in some
> hardware platforms. So, asynchronous resuming devices may
> hang system due to wrong resume order. As a result, should
> not fore synchronously resuming devices during tracing
> PM events.
> 
> Signed-off-by: Zhonghui Fu <zhonghui.fu@...ux.intel.com>
> ---
>  drivers/base/power/main.c    |    3 +--
>  include/linux/resume-trace.h |    7 -------
>  2 files changed, 1 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 9717d5f..5df148b 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -517,8 +517,7 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
>  
>  static bool is_async(struct device *dev)
>  {
> -	return dev->power.async_suspend && pm_async_enabled
> -		&& !pm_trace_is_enabled();
> +	return dev->power.async_suspend && pm_async_enabled;
>  }
>

Actually... whoever did the original patch was evil person. Changing
behaviour when tracing is requested is evil, evil, evil. Git blame
tells me

Signed-off-by: Chuansheng Liu <chuansheng.liu@...el.com>

went to the dark side.

									Pavel

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