Re: Fake KEY_5 continuous keydown events with Logitech wireless keyboard on Kernel 4.2

[Mauro Carvalho Chehab <mchehab@osg.samsung.com>]

Em Fri, 06 Nov 2015 17:37:55 +0100
Benjamin Tissoires <benjamin.tissoires@gmail.com> escreveu:

> HI Mauro,
> 
> On Fri, Nov 6, 2015 at 2:50 PM, Mauro Carvalho Chehab
> <mchehab@osg.samsung.com> wrote:
> > Hi Dmitry,
> >
> > Since I upgraded my desktop to Fedora 23 (with comes with Kernel 4.2.5), I'm
> > noticing a weird bug... from time to time, it starts producing an endless
> > sequence of KEY_5 events.
> >
> > I opened a bug at Fedora:
> >         https://bugzilla.redhat.com/show_bug.cgi?id=1278818
> >
> > But I suspect it could be some Kernel bug. Do you know if some change
> > between 4.1 and 4.2 might have triggered such bug?
> 
> I don't think any changes in 4.2 would trigger that. The only
> hid-logitech-hidpp change in 4.2 is unrelated to this particular
> keyboard and I don't think it could interfere with other devices than
> the M560.
> 
> 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:
> You can parse the output of the raw events by using
> ./tools/parse_hid.py in the hid-replay repository. Recording at the
> Unifying receiver level should give a bunch of HID reports
> encapsulated in the DJ protocol so parse_hid will not be able to parse
> them accurately. If you register the keyboard node, parse_hid.py
> should accurately translate the raw events to a human description of
> the report which should allow you to strip the sensitive data.

Parsed hid for the keyboard for 
	/dev/hidraw2:	Logitech K520
follows:

 68.090688 ReportID: 1 / LeftControl: 0 | LeftShift: 0 | LeftAlt: 0 | Left GUI: 0 | RightControl: 0 | RightShift: 0 | RightAlt: 0 | Right GUI: 0 |Keyboard [Return (ENTER), 00, 00, 00, 00, 00] 
 68.170687 ReportID: 1 / LeftControl: 0 | LeftShift: 0 | LeftAlt: 0 | Left GUI: 0 | RightControl: 0 | RightShift: 0 | RightAlt: 0 | Right GUI: 0 |Keyboard [00, 00, 00, 00, 00, 00] 
177.191904 ReportID: 16 /Vendor Defined Page 1 [02, 81, 07, 07, 00, 00] 
297.115254 ReportID: 16 /Vendor Defined Page 1 [02, 81, 07, 07, 00, 00] 
367.914151 ReportID: 16 /Vendor Defined Page 1 [02, 41, 04, 71, 11, 20] 
367.916051 ReportID: 1 / LeftControl: 0 | LeftShift: 0 | LeftAlt: 0 | Left GUI: 0 | RightControl: 0 | RightShift: 0 | RightAlt: 0 | Right GUI: 0 |Keyboard [00, 00, 00, 00, 00, 00] 
367.916062 ReportID: 3 /Consumer Devices [, ] 
367.916067 ReportID: 4 /Generic Desktop [] | # 
416.840646 ReportID: 16 /Vendor Defined Page 1 [02, 8f, 81, 07, 09, 00] 
476.573316 ReportID: 16 /Vendor Defined Page 1 [02, 41, 04, b1, 11, 20] 
476.577354 ReportID: 1 / LeftControl: 0 | LeftShift: 0 | LeftAlt: 0 | Left GUI: 0 | RightControl: 0 | RightShift: 0 | RightAlt: 0 | Right GUI: 0 |Keyboard [DELETE (Backspace), 00, 00, 00, 00, 00] 
476.671297 ReportID: 1 / LeftControl: 0 | LeftShift: 0 | LeftAlt: 0 | Left GUI: 0 | RightControl: 0 | RightShift: 0 | RightAlt: 0 | Right GUI: 0 |Keyboard [00, 00, 00, 00, 00, 00] 

I used the DEL key to delete the sequence of "5" that appeared there.

Please let me know if the above helps, of if I need to parse also the
mouse events.

Regards,
Mauro