Surface Laptop 3: Keyboard/Touchpad support

[qzed]

Implement keyboard and touchpad support for Surface Laptop 3.

Keyboard event dump: https://pastebin.com/cVj3Q9xF
Touchpad event dump: https://pastebin.com/c65QTcMd

[heapwolf]

@qzed I have a surface laptop 3 if you need any help! :)

[qzed]

@heapwolf Thank you for the offer, could you upload the output of ls -l /sys/bus/acpi/devices and ls -l /sys/bus/platform/devices?

[heapwolf]

@qzed definitely, at the moment i'm still trying to get it booted. See #591.

[Michielnuyts]

I own the Surface Laptop 3 15" AMD Ryzen 5, let me know if I can help with something.

[archseer]

I got the keyboard working (on SL3 13") with these changes: archseer@8b6c4a5

It's a bit of a hack but it should work until we can get a more proper patch.

[archseer]

Some notes: RQID is now 0x0015 and TC is also 0x15. A the keyboard frame type is now 0x00 while the touchpad uses 0x80 that was used for all commands previously.

HID is 1 for keyboard, but 2 for touchpad so with some more tweaking we can probably get that working too. (might need a separate driver?)

Keyboard:

00000000: [aa 55 start] [00 frame type] [14 length] [00 padding] [4d sequence] [0a 82 crc] command-frame-start -> [80 type] [15 target] [00 02 always this] [00 subcontroller] [15 00 request id, event id] [00 command id]
00000010: [01 hid?] [00 modifier?] [13 key code?] 00 00 00 00 00 00 00 00 00 [32 46 crc] <-- hid report

Touchpad:

00000000: [aa 55 start] [80 frame type] [0e length] [00 padding] [f1 sequence] [c7 bd crc] command-frame-start -> [80 type] [15 target] [00 02 always this] [00 subcontroller] [15 00 request id, event id] [00 command id]
00000010: [02 hid] [00 modifier?] ff 01 00 00 [3c db crc] <-- hid report

[archseer]

We'll need to construct a HID descriptor for the touchpad. The touchpad payload consists of:

[02 report id] [00 button] [ff 01 direction] [00 00 ?] [3c db crc]

• Button being 01 for left click, 02 for right click (right side of trackpad).
• Direction being ff 00 for left, 01 00 for right, 00 ff for up, 00 01 for down, so it seems to be just relative directions, not actual X and Y.

I think the second pair could be tracking for a second finger or something but I wasn't able to get it to be non-zero. Maybe it has to be enabled via the ACPI or something.

Been trying to modify

    //MOUSE TLC
    0x05, 0x01,                         // USAGE_PAGE (Generic Desktop)     
    0x09, 0x02,                         // USAGE (Mouse)                 
    0xa1, 0x01,                         // COLLECTION (Application)        
    0x85, 0x02,                         //   REPORT_ID (Mouse) (2)           
    0x09, 0x01,                         //   USAGE (Pointer)                
    0xa1, 0x00,                         //   COLLECTION (Physical)          
    0x05, 0x09,                         //     USAGE_PAGE (Button)          
    0x19, 0x01,                         //     USAGE_MINIMUM (Button 1)     
    0x29, 0x02,                         //     USAGE_MAXIMUM (Button 2)     
    0x25, 0x01,                         //     LOGICAL_MAXIMUM (1)          
    0x75, 0x01,                         //     REPORT_SIZE (1)              
    0x95, 0x02,                         //     REPORT_COUNT (2)             
    0x81, 0x02,                         //     INPUT (Data,Var,Abs)         
    0x95, 0x06,                         //     REPORT_COUNT (6)             
    0x81, 0x03,                         //     INPUT (Cnst,Var,Abs)         
    0x05, 0x01,                         //     USAGE_PAGE (Generic Desktop) 
    0x09, 0x30,                         //     USAGE (X)                    
    0x09, 0x31,                         //     USAGE (Y)                    
    0x75, 0x10,                         //     REPORT_SIZE (16)             
    0x95, 0x02,                         //     REPORT_COUNT (2)             
    0x25, 0x0a,                          //    LOGICAL_MAXIMUM (10)      
    0x81, 0x06,                         //     INPUT (Data,Var,Rel)         
    0xc0,                               //   END_COLLECTION                 
    0xc0,                                //END_COLLECTION    

https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/windows-precision-touchpad-sample-report-descriptors

[archseer]

I added the missing mouse descriptor by hand based on the windows precision touchpad example and now touchpad works as well 🎊All I had to do was modify it from three mouse buttons to two.

archseer@f79b821

[archseer]

By default, the touchpad works as a plain mouse (no gestures). It seems that to get the touchpad working as a touchpad/digitizer, there's some extra steps involved:

https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/windows-precision-touchpad-required-hid-top-level-collections#configuration-collection

We should also be able to talk to the EC to retrieve the HID descriptors instead of hardcoding them (somehow).