Message-ID: <Z2RxW6K-_Ujrxeim@google.com>
Date: Thu, 19 Dec 2024 11:17:47 -0800
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Mark Pearson <mpearson-lenovo@...ebb.ca>
Cc: Hans de Goede <hdegoede@...hat.com>,
	Peter Hutterer <peter.hutterer@...hat.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: atkbd: Fix so copilot key generates F23 keycode

On Thu, Dec 19, 2024 at 01:40:24PM -0500, Mark Pearson wrote:
> On Thu, Dec 19, 2024, at 1:31 PM, Dmitry Torokhov wrote:
> > On Thu, Dec 19, 2024 at 07:26:19PM +0100, Hans de Goede wrote:
> >> Hi,
> >> 
> >> On 19-Dec-24 7:15 PM, Dmitry Torokhov wrote:
> >> > Hi,
> >> > 
> >> > On Thu, Dec 19, 2024 at 05:01:09PM +0100, Hans de Goede wrote:
> >> >> Hi,
> >> >>
> >> >> Really +Cc Peter Hutterer this time.
> >> >>
> >> >> On 19-Dec-24 4:48 PM, Mark Pearson wrote:
> >> >>> Hi Hans
> >> >>>
> >> >>> On Thu, Dec 19, 2024, at 10:28 AM, Hans de Goede wrote:
> >> >>>> +Cc Peter Hutterer
> >> >>>
> >> >>> My bad - I've been discussing this with Peter and should have added him. Thanks for including (sorry Peter!)
> >> >>
> >> >> Except I forgot to actually add Peter...
> >> >>
> >> >>>> Hi Mark,
> >> >>>>
> >> >>>> Thank you for your patch.
> >> >>>>
> >> >>>> On 19-Dec-24 4:18 PM, Mark Pearson wrote:
> >> >>>>> The copilot key on Lenovo laptops doesn't work as scancode 0x6e, which it
> >> >>>>> generates is not mapped.
> >> >>>>> This change lets scancode 0x6e generate keycode 193 (F23 key) which is
> >> >>>>> the expected value for copilot.
> >> >>>>>
> >> >>>>> Tested on T14s G6 AMD.
> >> >>>>> I've had reports from other users that their ThinkBooks are using the same
> >> >>>>> scancode.
> >> >>>>
> >> >>>> Hmm, I'm not sure mapping this to KEY_F23 is the right thing to do,
> >> >>>> there are 2 issues with this approach:
> >> >>>>
> >> >>>> 1. /usr/share/X11/xkb/symbols/inet currently maps this to
> >> >>>>    XF86TouchpadOff as F20 - F23 where repurposed to
> >> >>>>    TouchPad on/off/toggle / micmute to work around X11
> >> >>>>    not allowing key-codes > 247.
> >> >>>>
> >> >>>>    We are actually working on removing this X11 workaround
> >> >>>>    to make F20-F23 available as normal key-codes again
> >> >>>>    for keyboards which actually have such keys.
> >> >>>>
> >> >>>> 2. There are some keyboards which have an actual F23 key
> >> >>>>    and mapping the co-pilot key to that and then having
> >> >>>>    desktop environments grow default keybindings on top
> >> >>>>    of that will basically mean clobbering the F23 key or
> >> >>>>    at least making it harder to use.
> >> >>>>
> >> >>>> I think was is necessary instead is to add a new
> >> >>>> KEY_COPILOT to include/uapi/linux/input-event-codes.h
> >> >>>> and use that instead.
> >> > 
> >> > We have discussed this with Peter and came to the conclusion that
> >> > KEY_ASSISTANT should cover this use case.
> >> > 
> >> > Also, this tweak should go into udev rules (/lib/udev/hwdb.d/60-keyboard.hwdb)
> >> > instead of adding a vendor-specific tweak to the main atkbd table.
> >> > 
> >> > For the future releases you may want to add "linux,keymap" device
> >> > property to your ACPI/DSDT to control the scancode->keycode mapping when
> >> > Linux is running.
> 
> I can look into this, but gut feeling is it's a bad solution for the Linux ecosystem as it will limit it to only platforms in the Lenovo Linux program. Be nicer to have a more widespread solution.
> 
> >> > 
> >> >>>
> >> >>> Sorry, should have been clearer in the commit message.
> >> >>> I'm doing this just on the Microsoft spec. The co-pilot key is left-shift, Windows/Meta key, F23. Weird combo I know....
> >> >>>
> >> >>> Somewhere I had a MS page...but this Tom's HW page mentions it:
> >> >>> https://www.tomshardware.com/software/windows/windows-copilot-key-is-secretly-from-the-ibm-era-but-you-can-remap-it-with-the-right-tools
> >> >>>
> >> >>> I'll see if I can find something more formal.
> >> >>>
> >> >>>>
> >> >>>> Peter, I thought I read somewhere that you were looking
> >> >>>> into mapping the copilot key to a new  KEY_COPILOT evdev
> >> >>>> key for some other keyboards?
> >> >>>>
> >> >>>
> >> >>> Wouldn't this require the kernel catching all three key events and doing the interpretation? I have no idea how this would be done or if it makes sense.
> >> >>
> >> >> So I guess I got caught off guard by your commit message
> >> >> which suggests that only scancode 0x6e is generated.
> >> >>
> >> >> If indeed a left-shift + Windows/Meta key + 0x6e combination
> >> >> is send them this is a different story, since indeed we
> >> >> cannot filter on that in the kernel. Although sometimes
> >> >> I wonder if we should because we are seeing similar things
> >> >> where left-shift + Windows/Meta key + xxxx is send for
> >> >> e.g. touchpad on/off toggle.
> >> >>
> >> >> To workaround this atm GNOME listens for XF86TouchpadToggle
> >> >> as well as shift + meta + XF86TouchpadToggle, theoretically it
> >> >> would be nice if we can recognize these special key-combos at
> >> >> a lower level. But thinking about this that is nasty, because
> >> >> then we would get an event sequence like this:
> >> >>
> >> >> Report shift pressed
> >> >> Report meta pressed
> >> > 
> >> > No, you have to delay to see if it is real press or part of sequence.
> >> > 
> >> >> <oops special key, release them>
> >> >> Report meta released
> >> >> Report shift released
> >> >> Report KEY_TOUCHPAD_TOGGLE
> >> >> <and what do we do with the modifiers now?
> >> >>  for correctness I guess we report them
> >> >>  as pressed again until the hw reports them released>
> >> >> Report shift pressed
> >> >> Report meta pressed
> >> >> <hw releases the fake modifiers>
> >> >> Report meta released
> >> >> Report shift released
> >> >>
> >> >> So yeah handling this in the kernel is not going to be pretty.
> >> > 
> >> > Yes, we have a form of this in drivers/tty/sysrq.c and it indeed is not
> >> > pretty.
> >> > 
> >> >>
> >> >> So I think your right and just mapping this to F23 is probably
> >> >> best, but I would like to hear what Peter thinks first.
> >> > 
> >> > So vendor yet again encoded a shortcut sequence into firmware,
> >> > beautiful. I guess you can try to install a 8042 filter
> >> > (via i8042_add_filter()) in drivers/platform/x86/lenovo-<something>.c
> >> > to monitor for this specific scancode sequence and replace it with
> >> > something else (through an auxiliary input device). 
> >> 
> >> If we want to filter out these in essence fake modifier
> >> events then this needs to be done at some core level,
> >> because AFAIK the shift + meta + F23 key-combo is what
> >> microsoft is telling OEMs to use, so we are going to see this on
> >> laptops from all vendors including whitelabel laptops.
> >
> > Hm, then I'd rather leave it to the userspace shortcut handling to deal
> > with. It's probably gonna disappear the same way as others in a couple
> > of years ;) and be replaced with some thing else.
> >
> > And mapping to F23 as I said should be done through udev. I doubt they
> > will get all OEMs settle on the same scancode.
> >
> 
> I'll see if we can find a way to check on other vendor platforms what scancode is used.
> If it is a common scancode, across multiple vendors, would the patch be acceptable?

It is currently unmapped by default, so maybe.

FWIW:

dtor@...r-ws:~/kernel/work $ grep KEY_6e /lib/udev/hwdb.d/60-keyboard.hwdb
KEYBOARD_KEY_6e=wlan
KEYBOARD_KEY_6e=left                                   # left on d-pad
KEYBOARD_KEY_6e=search

That 2nd entry is actually from one of Thinkpad models ;)

Thanks.

-- 
Dmitry

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