linux-kernel - Re: [2.6.24-rc1 regression] AC adapter state does not change after resume

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Message-Id: <200711012144.12477.arvidjaar@mail.ru>
Date:	Thu, 1 Nov 2007 21:44:02 +0300
From:	Andrey Borzenkov <arvidjaar@...l.ru>
To:	Alexey Starikovskiy <aystarik@...il.com>
Cc:	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: [2.6.24-rc1 regression] AC adapter state does not change after resume

On Wednesday 31 October 2007, Alexey Starikovskiy wrote:
> Andrey Borzenkov wrote:
> > On Wednesday 31 October 2007, Alexey Starikovskiy wrote:
> >> Andrey Borzenkov wrote:
> >>> I suspect new ACPI AC adapter code but have to add some printk's to be
> >>> sure.
> >>>
> >>> To reproduce - plug in AC cord, suspend, unplug, resume - kpowersave
> >>> and sysfs still show AC adapter online. Or other way round.
> >>>
> >>> -andrey
> >>
> >> Please check if this patch helps.
> >
> > It does not even compile :)
> >
> > On serious note (after adding forward declaration) - patch half works. It
> > does make "online" return true value (which confirms that underlying ACPI
> > works correctly) but HAL still does not notice it.
> >
> > The problem is, with power_supply interface HAL does not use polling, it
> > relies on CHANGE event. This event is apparently never generated if AC
> > adapter state changes on resume. So the obvious fix is to compare AC
> > state before and after suspend in ->resume function and generate
> > synthetic CHANGE event if something has changed.
> >
> > This will also make superfluous polling redundant.
>
> Ok, here. This one compiles :)
>

For HAL regression:

Tested-by: Andrey Borzenkov <arvidjaar@...l.ru>

But the patch is incomplete. This synthetic event should be the same as if OS 
were running; i.e. you should send both other events as well. As is you just 
create latent bug to be hit by some netlink consumer sooner or later.

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