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

[Shem Multinymous]

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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