Re: HID: asus: Add T100CHI bluetooth keyboard dock touchpad support

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 15-11-17 11:38, Tj wrote:
> Hans: I replied to the l.i. mailing list yesterday regarding your July
> patches for the Asus T100CHI in the 4.14 kernel but accidentally left
> you off the CC list, so I'm following up now.
> 
> This is on a T300CHI - the HID report descriptor looks identical to the
> T100CHI and the report descriptor fix-up enables the special function keys.
> 
> I've confirmed that even after powering off the Bluetooth Dock it
> remains in multi-touch mode and therefore has no functionality when
> booting with an earlier kernel where mouse mode is expected.
> 
> I did quite a few experiments and permutations powering it off and on
> again including after booting into the earlier kernel and entering the GUI.
> 
> I eventually found a way to force it to reset: running hid-recorder and
> turning the dock off whilst doing some multi-touch action!
> 
> This also allowed me to confirm that on the earlier kernels (pre v4.14),
> in 'mouse' mode, single finger singe/double taps on the touchpad
> (anywhere on it's surface) work as single/double-click mouse actions,
> including the separate right-button-area tap usually used for context menu.
> 
> So it seems like there are two bugs here:
> 
> 1) driver needs to put the touchpad back into mouse mode on exit

Hmm, the problem here is that requires us to know the command to send
to put it back into mouse mode, which we don't. We do not have documentation
for these devices.

> 2) single-finger taps need to be handled as position-sensitive mouse
> clicks (left or right button).

Erm, no, that is not how clickpads work, if you want finger position
dependent left or right clicks you need to actually "click" the
clickpad.

You can enable tap-to-click in your desktop environments config
panel and then a single finger tap anywhere will do a left clock,
for a right click use a 2-finger tap.

Regards,

Hans



> 
> Let me know if you need any additional debugging/data capture.
> 
> The information in my earlier email is still pertinent:
> 
> On 14/11/17 20:09, Tj wrote:
>> With kernel v4.14 on an Asus T300CHI this appears to be working up to a
>> point but it causes the touchpad to FAIL to work on earlier kernels.
>>
>> The touchpad seems to be in multitouch mode (two-finger scrolling is the
>> only MT action I've confirmed so far) but there are some deficiencies.
>>
>> For instance, single or double-tap on the touchpad, or tapping the
>> left/right 'button' regions doesn't work.
>>
>> This touchpad is overlaid on a physical 'click' button surface (which I
>> suspect operates as the mouse). By this I mean instead of lightly
>> tapping the touchpad surface it needs a very firm downward movement
>> until a physical 'click' is heard. It resists quite strongly so
>> double-clicks in particular are difficult. There's a separate physical
>> 'click' area for the right button.
>>
>> So it works with these hard physical 'click' actions but not when
>> tapping the touchpad surface. To compare with the behaviour under
>> previous kernels (where I seem to recall it only needed touchpad taps) I
>> rebooted into an earlier kernel.
>>
>> The disturbing FAILURE is that if the T300CHI is rebooted - even if from
>> a poweroff - into an earlier kernel version (than v4.14) the touchpad no
>> longer works.
>>
>> Using hid-recorder I saw that the touchpad is still in multitouch mode
>> (event descriptor id 0x5D rather than 0x06 when doing multitouches).
>>
>> So far I've not been able to find a way to workaround/fix this. On the
>> face of it the driver needs to put the touchpad back into 'mouse' mode
>> on shutdown.
>>