Re: PROBLEM: atkbd: Incorrect (?) handling of BAT from laptop PS/2 keyboard

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Alexander,

On Sun, Jul 02, 2017 at 04:32:18AM +0300, Alexander Babayants wrote:
> Hi,
> 
> HP Pavilion 15 keyboard controller sometimes (as far as I've found, at
> least after keyboard (re-)connection and LED status change) emits 0xAA
> scancode (BAT passed) and key-up events for LCtrl, LAlt, RCtrl, RAlt,
> RShift. This, in turn, causes the keyboard to reconnect
> (drivers/input/keyboard/atkbd.c, line 424) and to emit 0xAA scancode again,
> which results in keyboard being stuck in endless loop of reconnecting.
> While in this loop, keyboard is usable, but some keystrokes are being
> occasionally dropped.
> Is it necessary to handle BAT scancode in such particular way? Couldn't it
> just be ignored?

We should not ignore BAT, as it normally indicates that the keyboard
lost its state and we need to re-initialize it (update LED state to be
in sync with the keyboard state, set up repeat rate, select proper set -
2 or 3, etc).

I would be interesting to see the command stream there. Can you try
booting with i8042.debug and reproducing the issue?

Thanks.

-- 
Dmitry