linux-kernel - Re: [PATCH] Input: psmouse - disable automatic probing of BYD touchpads

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Date:   Sat, 12 Nov 2016 23:13:31 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Pali Rohár <pali.rohar@...il.com>
Cc:     "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Chris Diamand <chris@...mand.org>,
        Frederick Billings <phonesyfreakies@...il.com>,
        Michael Shell <list1@...haelshell.org>,
        Eric Wong <normalperson@...t.net>,
        Ondrej Zary <linux@...nbow-software.org>,
        Christophe TORDEUX <christophe@...deux.net>,
        Richard Pospesel <pospeselr@...il.com>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Input: psmouse - disable automatic probing of BYD touchpads

On Sat, Nov 12, 2016 at 11:39 AM, Pali Rohár <pali.rohar@...il.com> wrote:
> On Saturday 12 November 2016 20:15:45 Dmitry Torokhov wrote:
>> BYD automatic protocol detection is extremely unreliable and is often
>> triggers false positives on regular mice, Sentelic touchpads, and
>> other devices. BYD has several documents that have recommended
>> detection sequence, but they conflict with each other and, as far as
>> I can see, still would not produce unique enough output to reliably
>> differentiate BYD from other PS/2 devices.
>>
>> OEMs sourcing BYD devices also do not do us any favors by not
>> supplying any reasonable DMI data and instead leaving turds like "To
>> Be Filled By O.E.M." in place of vendor data, or "System Serial
>> Number" as serial number.
> ...
>>       echo -n "byd" > /sys/bus/serio/devices/serio1/drvctl
>
> I agree, if we cannot detect BYD devices correctly without breaking
> other non-BYD devices then detection must be done by user...
>
> So you can add my Reviewed-by: Pali Rohár to this patch.
>
> Anyway, BYD show Linux as supported OS for their devices. It is really
> rude from BYD that they show Linux as supported OS, but Linux driver is
> reverse-engineered by community and they do not want to cooperate and at
> least provide some useful documentation for detection...

I am not even sure they have a good way of detecting their devices.
The Windows model is that vendor supplies OEM with their driver and it
just works (I do not think these devices have external PS/2 ports so
there is no concern with mis-detection).

Thanks.

-- 
Dmitry