Re: [PATCH] backlight dimmer

From: jack
Date: Sun Oct 28 2007 - 18:10:40 EST


Arjan van de Ven wrote:
On Sun, 28 Oct 2007 22:30:55 +0100
"lists@xxxxxxxxxxxxx" <lists@xxxxxxxxxxxxx> wrote:

Ok,
now checkpatch.pl only complains about a missing signed-off-by.
Is this ok for review?


hi,

when going over your patch.. is there a reason you introduce yet
another timeout infrastructure? Is there something wrong with the
existing ones that maybe should be fixed instead?
Either way.. please put justification for such new mechanism in the
patch changelog....

Greetings,
Arjan van de Ven


hi,

i don't think there are similar infrastructures. This timeout is
not quite a timer.

The timeout starts counting when timeout_touch() is first called. At
this point the start() function is executed in non-atomic context.
Then either it is reset if timeout_touch() is called in time (and
thus starts to count again). Else it triggers, and executes the
trigger() function in non-atomic context and it stays idle unless
timeout_touch() is called again.

The non-atomic context is needed to use backlight.c mutexes and
that is enabled with the use of workqueues.

I don't mean to add some new infrastructure to the base kernel, but
it seemed a general functionality to me. In fact it may also be fully
included in backlight.c. Since backlight.h is in include/linux, i was
forced to put timeout.h in include/linux also. But this is just
a temporary fix.

jacopo

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