2015-11-06 17:37 GMT+01:00 Benjamin Tissoires [off-list ref]:

I also experienced such problems from time to time and always thought
it was either a firmware problem or a low battery issue. When
recharging my keyboard, the issue disappeared. Unfortunately, I was
never able to figure out which HID raw event triggered this kernel key
repeat (as you said, it's random).

Now that I think of it, I might have a reproducer here. When playing
with libratbag to configure the MX Master, I receive from time to time
some key events while no keys should be sent by the mouse. I suspect
that the HID parsing convert some internal protocol events into HID
keys and generate spurious keys. I'll check on this.

If you can manage to reproduce your issue more often (for me, this
happens once in a month or so), I'd be curious to check the HID raw
events coming out from the keyboard just before the bug, and what
triggers the bug.
I'd be glad if you could do a recording with hid-record (from
hid-replay[1]). Make sure that the logs do not contain sensitive
information:

Hi Benjamin,

I think I got this bug while testing writing profiles to my Logitech
G500 (with Fedora 23, kernel 4.2.6, it uses hid-generic driver not the
hidpp or dj ones) except I got only one press/release pair for each
page I wrote. I was able to reproduce that several times in a row but
there was only the expected HID++ reports and hid-replay did not
reproduce the bug.

I am not sure what caused the events exactly, it happened around the
time I write the 0xa1 register for resetting the sequence number.
Then, I tried only writing the 0xa1 register, I got a lot of KEY_5
events. I was not able to reproduce anything after that.

An extract of the output of both evtest and hid-recorder running at
the same time:
E: 0.357976 7 10 00 82 a0 00 00 00
E: 0.359965 7 10 00 80 a1 00 00 00
Event: time 1450279569.586206, type 4 (EV_MSC), code 4 (MSC_SCAN),
value ffff8802
Event: time 1450279569.586206, type 1 (EV_KEY), code 6 (KEY_5), value 1
Event: time 1450279569.586206, -------------- SYN_REPORT ------------
Event: time 1450279569.588202, E: 0.361963 7 10 00 50 01 00 00 00
type 4 (EV_MSC), code 4 (MSC_SCAN), value ffff8802
Event: time 1450279569.588202, type 1 (EV_KEY), code 6 (KEY_5), value 0
Event: time 1450279569.588202, -------------- SYN_REPORT ------------
E: 0.364983 7 10 00 50 01 01 00 00
E: 0.367920 7 10 00 50 01 02 00 00
E: 0.370938 7 10 00 50 01 03 00 00
E: 0.374948 7 10 00 50 01 04 00 00
Note that there is a HID++ answer (the acknowledgment notification
from the first packet) in the middle of an evtest line.

Debug output from my program (unlike libratbag, I write pages directly
to flash 512 bytes at once):
...
[Debug] Setting long register 0xa0
[Debug] Parameters: 02 00 00 00 00 00 04 00 00 00 00 00 00 00 00 00
[Debug] Setting short register 0xa1
[Debug] Parameters: 01 00 00
[Debug] Sending data packet 0
[Debug] (Data packet 01 04 00 00 00 02 00 00 00 ff 00 00 80 00 11 00
[Debug] Data packet 0 acknowledged
[Debug] Sending data packet 1
[Debug] Data packet 11 22 11 00 22 00 22 22 12 00 55 00 55 22 22 00
[Debug] Data packet 1 acknowledged
...
[Debug] Setting long register 0xa0
[Debug] Parameters: 02 00 00 00 00 00 05 00 00 00 00 00 00 00 00 00
[Debug] Setting short register 0xa1
[Debug] Parameters: 01 00 00
[Debug] Sending data packet 0
[Debug] Data packet 01 05 00 00 00 02 00 00 00 22 04 20 2b 21 2b 61
([Debug] Data packet 0 acknowledged
[Debug] Sending data packet 1
[Debug] Data packet 01 90 05 0a 00 20 2b 21 2b c0 45 05 06 23 04 ff
...
The parentheses in "(Data" or "([Debug]" are KEY_5 on my french AZERTY keyboard.

I hope this can help.