Re: [PATCH] - race-free suspend. Was: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8)

From: Florian Mickler
Date: Wed Jun 02 2010 - 04:50:55 EST


On Wed, 2 Jun 2010 18:06:14 +1000
Neil Brown <neilb@xxxxxxx> wrote:

> I cannot imagine why it would take multiple seconds to scan a keypad.
> Can you explain that?
>
> Do you mean while keys are held pressed? Maybe you don't get a wake-up event
> on key-release? In that case your user-space daemon could block suspend
> while there are any pressed keys.... confused.

IIRC, the device sends interrupts only for first key-down and
last key-up.
To detect simultaneous key-presses you must actively scan it after the
first key-down.


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