Comment 41 for bug 1366421

> intel-vbtn.c really seems to handle power buttons only.
Patches necessary for Dell Venue 11 Pro 7140 is here:
https://bugzilla.kernel.org/show_bug.cgi?id=102281#c78
https://bugzilla.kernel.org/show_bug.cgi?id=102281#c83
Hopefully it doesn't take long time for merging it.

> Could you too check if the list of devices changes between tablet and laptop-mode?
I doesn't have keyboard dock for my tablet, however I have access to Thinkpad Helix 1gen and DEXP Ursus 10XW.

About DEXP devices. They produce many tablets with keyboard, please take a look:
http://dexp.club/Products/Planshety?Archive=True&ViewType=Table&Operacionnaya-sistema=38428
http://dexp.club/Products/Planshety?Archive=True&ViewType=Table&Operacionnaya-sistema=40425
http://dexp.club/Products/Planshety?ViewType=Table&Operacionnaya-sistema=38428
http://dexp.club/Products/Planshety?ViewType=Table&Operacionnaya-sistema=40425
14 tablets with keyboards as you can see. All of them works in exactly same way - folio with keyboard and touchpad is USB device.

Test on DEXP Ursus 10XW tablet:
evtest1, xinput1 - folio with keyboard is not attached yet.
evtest2, xinput2 - folio with keyboard attached.
evtest3, xinput3 - folio with keyboard deattached.
Here is logs:
Shrotly, when folio with keyboard is attached, HID 0911:2188 device appear in evtest and xinput output, when folio with keyboard is deattached - device simply disappear from evtest and xinput.

Test on Thinkpad Helix 1gen:
/sys/devices/platform/thinkpad_acpi/hotkey_tablet_mode flag works as expected (0 with keyboard, 1 without it).

Well, to sum up things I guess there is no easy way to determine if keyboard is attached or not: USB device in DEXP case, hotkey_tablet_mode flag in Helix case, ThinkPad Extra Buttons in Yoga case, intel-vbtn in Venue 11 Pro 7140 case, etc.
Maybe you should contact Unity 8 and Gnome Shell developers to discuss how to do that in more universal way? Something like iio-sensor-proxy (or maybe ask iio-sensor-proxy developers to add support for that?) that could be useful not only for onboard but also for DEs. I pretty sure Unity 8 will benefit from automatic mode detection. Gnome Shell could use that for their own onscreen keyboard too.

By the way I find that disabling "auto-show" option is not working, after tablet reboot (and possible after re-login or onboard restart) this option always reset to enabled state. Do I need to fill separate bugreport about that?