linux-kernel - Re: [rfd] saving old mice -- button glitching/debouncing

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Message-ID: <20181215101221.GA23879@suse.com>
Date:   Sat, 15 Dec 2018 11:12:21 +0100
From:   Vojtech Pavlik <vojtech@...e.cz>
To:     Pavel Machek <pavel@....cz>
Cc:     kernel list <linux-kernel@...r.kernel.org>, jikos@...e.cz,
        linux-input@...r.kernel.org, dmitry.torokhov@...il.com
Subject: Re: [rfd] saving old mice -- button glitching/debouncing

On Sat, Dec 15, 2018 at 10:47:22AM +0100, Pavel Machek wrote:

> > > b) would it be acceptable if done properly? (cmd line option to
> > > enable, avoiding duplicate/wrong events?)
> > 
> > Well, for one, you shouldn't be using a timer, all the debouncing can be
> > done by math on the event timestamps.
> 
> Not... really, right? You need to send an release some time after
> button indicates release if bounce did not happen. It is similar to
> autorepeat needing a timer.

You can send the first release and ignore all presses and releases in a
time window after that.

> Let me gain some experience with the patch. I don't think hardware
> does as heavy debouncing as you describe.

Microswitches vibrate significantly when clicked. Without hardware
debouncing, you'd have many clicks instead of one even on a new mouse.


-- 
Vojtech Pavlik