Re: [PATCH 1/4] Input: Add trackpoint doubletap and system debug info keycodes

[Dmitry Torokhov]

On Mon, Apr 15, 2024 at 09:47:10PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 4/15/24 9:35 PM, Dmitry Torokhov wrote:
> > On Thu, Apr 11, 2024 at 02:30:35PM +0200, Hans de Goede wrote:
> >> Hi Dmitry,
> >>
> >> On 4/11/24 2:02 AM, Dmitry Torokhov wrote:
> >>> On Tue, Apr 09, 2024 at 10:17:05PM -0400, Mark Pearson wrote:
> >>>> Hi Dmitry
> >>>>
> >>>> On Tue, Apr 9, 2024, at 9:20 PM, Dmitry Torokhov wrote:
> >>>>> On Tue, Apr 09, 2024 at 02:47:05PM -0700, Dmitry Torokhov wrote:
> >>>>>> On Tue, Apr 09, 2024 at 03:23:52PM +1000, Peter Hutterer wrote:
> >>>>>>> On 09/04/2024 09:31, Dmitry Torokhov wrote:
> >>>>>>>> Hi Mark,
> >>>>>>>>
> >>>>>>>> On Sun, Mar 24, 2024 at 05:07:58PM -0400, Mark Pearson wrote:
> >>>>>>>>> Add support for new input events on Lenovo laptops that need exporting to
> >>>>>>>>> user space.
> >>>>>>>>>
> >>>>>>>>> Lenovo trackpoints are adding the ability to generate a doubletap event.
> >>>>>>>>> Add a new keycode to allow this to be used by userspace.
> >>>>>>>>
> >>>>>>>> What is the intended meaning of this keycode? How does it differ from
> >>>>>>>> the driver sending BTN_LEFT press/release twice?
> >>>>>>>>>
> >>>>>>>>> Lenovo support is using FN+N with Windows to collect needed details for
> >>>>>>>>> support cases. Add a keycode so that we'll be able to provide similar
> >>>>>>>>> support on Linux.
> >>>>>>>>
> >>>>>>>> Is there a userspace consumer for this?
> >>>>>>>
> >>>>>>> Funnily enough XKB has had a keysym for this for decades but it's not
> >>>>>>> hooked up anywhere due to the way it's pointer keys accessibility
> >>>>>>> feature was implemented. Theory is that most of userspace just needs
> >>>>>>> to patch the various pieces together for the new evdev code + keysym,
> >>>>>>> it's not really any different to handling a volume key (except this
> >>>>>>> one needs to be assignable).
> >>>>>>
> >>>>>> What is the keysym? If we can make them relatable to each other that
> >>>>>> would be good. Or maybe we could find a matching usage from HID usage
> >>>>>> tables...
> >>>>>
> >>>>> I was looking through the existing codes and I see:
> >>>>>
> >>>>> #define KEY_INFO		0x166	/* AL OEM Features/Tips/Tutorial */
> >>>>>
> >>>>> We also have KEY_VENDOR used in a few drivers/plafrom/x86, including
> >>>>> thinkkpad_acpi.c and I wonder if it would be suitable for this vendor
> >>>>> specific debug info collection application (which I honestly doubt will
> >>>>> materialize).
> >>>>>
> >>>>
> >>>> That's a somewhat disappointing note on your doubts, is that based on
> >>>> anything? Just wondering what we've done to deserve that criticism.
> >>>
> >>> Sorry, this was not meant as a criticism really, but you mentioned
> >>> yourself that there isn't anything in the works yet, you just have some
> >>> plans.
> >>>
> >>> For such a project to succeed Lenovo needs to invest into selling
> >>> devices with Linux as a primary operating system, and it has to be
> >>> consumer segment (or small business, because for corporate they
> >>> typically roll their own support channels). The case of retrofitting
> >>> Linux onto a that device originally came with Windows OS rarely gets
> >>> much if any response from the normal support channels.
> >>>
> >>> Is this something that is actually happening?
> >>
> >> Yes, Lenovo is actually offering Fedora as an OS choice when
> >> ordering ThinkPads directly from their website in many countries
> >> including when ordering as a consumer.
> > 
> > Ah, very nice, I was not aware of this.
> > 
> >>
> >> And unlike other vendor's Linux preloads which often use a kernel
> >> with downstream laptop specific changes these laptops are running
> >> unmodified Fedora kernels, which themselves are almost pristine
> >> upstream kernels.
> >>
> >> Lenovo (Mark) has been really good the last couple of years in
> >> making sure that their hw just works with mainline kernels without
> >> any downstream vendor specific patches.
> >>
> >>>> That aside, I guess KEY_INFO or KEY_VENDOR could be a good fit (I
> >>>> personally don't think KEY_CONFIG matches well), but I would be
> >>>> worried about clashing with existing functionality.
> >>
> >> Using KEY_INFO / KEY_VENDOR works for me too. So maybe we should
> >> just go with one of those 2 ?
> > 
> > It looks like Mark's preference is KEY_VENDOR, so let's go with it?
> 
> Ack KEY_VENDOR sounds good to me for the doubletap on the trackpoint event.
> 
> What about the new Fn + N keycombo which also generates a WMI
> event which we want to translate to a key code to launch a
> (to be written) debug-info collecting app for when the customer
> calls Lenovo support.
> 
> Mark suggested a new KEY_SYS_DEBUG_INFO for that. So do we use:
> 
> #define KEY_INFO                0x166   /* AL OEM Features/Tips/Tutorial */
> 
> for this, or do we define a new keycode ?
> 
> Mark would using KEY_INFO for this work for you.
> 
> Dmitry any opinion on this ?

No, my understanding is that Mark was OK with using KEY_VENDOR for Fn+N
combination that is supposed to start the utility that would collect
the debug info.

For double click there is still the discussion whether to have
KEY_DOUBLECLICK (which I think will need to be tied to the pointer
device somehow), or something else, like KEY_CONFIG or a new keycode if
we continue keeping it separate from the pointer operations and match
Windows behavior which invokes Lenovo configuration utility.

Thanks.

-- 
Dmitry