Re: [PATCH 05/12] hdaps: Remember keyboard and mouse activity

From: Shem Multinymous
Date: Mon Aug 07 2006 - 12:16:57 EST


On 8/7/06, Pavel Machek <pavel@xxxxxxx> wrote:
> When the current hdaps driver is queried for recent keyboard/mouse activity
> (which is provided by the hardware for use in disk parking daemons), it
> simply returns the last readout. However, every hardware query resets the
> activity flag in the hardware, and this is triggered by (almost) any
> hdaps sysfs attribute read, so the flag could be reset before it is
> observed and is thus nearly useless.
>
> This patch makes the activities flags persist for 0.1sec, by remembering
> when was the last time we saw them set. This gives apps like the hdaps
> daemon enough time to poll the flag.

And should not hdapsd get it from input interface?

At this point the disk may parked and its queue frozen, and may depend
on the keyboard/mouse activity to be released. So hdapsd mustn't do
anything that involves potential swapping or userspace with unlocked
memory, and the input infrastructure is too large and flexible for
such a guarantee. I guess this is why IBM provided this low-level hook
at the embedded controller level.

Shem
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