From: Eduardo Valentin <edubezval@gmail.com>
To: Keerthy <j-keerthy@ti.com>
Cc: nm@ti.com, rui.zhang@intel.com, linux-pm@vger.kernel.org,
linux-omap@vger.kernel.org
Subject: Re: [PATCH] thermal: omap-thermal: Add notify function to thermal_zone_device_ops
Date: Tue, 8 Mar 2016 12:48:14 -0800 [thread overview]
Message-ID: <20160308204812.GA6800@localhost.localdomain> (raw)
In-Reply-To: <1455599145-5656-1-git-send-email-j-keerthy@ti.com>
On Tue, Feb 16, 2016 at 10:35:45AM +0530, Keerthy wrote:
> notify function is used to notify when some temperature thresholds
> are crossed. In case we get notified for a critical trip point then
> schedule an emergency shutdown function to backup orderly_poweroff
> failures.
>
> orderly_poweroff is triggered when a graceful shutdown
> of system is desired. This may be used in many critical states of the
> kernel such as when subsystems detects conditions such as critical
> temperature conditions. However, in certain conditions in system
> boot up sequences like those in the middle of driver probes being
> initiated, userspace will be unable to power off the system in a clean
> manner and leaves the system in a critical state. In cases like these,
> the /sbin/poweroff will return success (having forked off to attempt
> powering off the system. However, the system overall will fail to
> completely poweroff (since other modules will be probed) and the system
> is still functional with no userspace (since that would have shut itself
> off).
>
> However, there is no clean way of detecting such failure of userspace
> powering off the system. In such scenarios, it is necessary for a backup
> workqueue to be able to force a shutdown of the system when orderly
> shutdown is not successful after a configurable time period.
>
> Signed-off-by: Keerthy <j-keerthy@ti.com>
> ---
>
> The previous discussion:
>
> https://lkml.org/lkml/2016/1/28/989
>
> Making use of the notify ops to schedule a backup thermal shutdown.
Yeah, this was a bit of a stretching. If we cannot fix orderly power
off, I would say, better fixing it for all thermal drivers (previous
version of this). This patch:
1. Abuse a notify function to be used as a power off functions
2. Fix an issue only for a single driver.
I will check your initial version.
next prev parent reply other threads:[~2016-03-08 20:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-16 5:05 [PATCH] thermal: omap-thermal: Add notify function to thermal_zone_device_ops Keerthy
2016-03-07 7:31 ` Keerthy
2016-03-07 7:33 ` Keerthy
2016-03-08 20:48 ` Eduardo Valentin [this message]
2016-05-10 12:02 ` Keerthy
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