Hi, The MX Anywhere 2 mouse has a high-resolution wheel that allows sending wheel events together with mouse movements or in separate, via HID++. By default, it starts in low-resolution mode, reporting events via HID. The documentation for it was recently added[1]: https://lekensteyn.nl/files/logitech/x2121_hires_wheel.pdf [1] there's a small error at the documentation, though: On page 5, at "[event0] wheelMovement() → resolution, periods, deltaV" chapter, it says that the "periods" field can be up to 15, but it shows only 3 bits for it table 9 "wheelMovement() report packet", placing the high-resolution bit as bit 3. After investigating it in practice, the actual bit that changes when the wheel is in high-resolution mode is bit 4. When bit = 1, the mouse is using high-resolution; when 0, it is using low resolution. So, in summary, the correct information there at the table should be, instead: - bits 0-3: periods - bit 4: resolution There is a BZ for Solaar userspace application, opened in Aug, 2016 requesting support for it: https://github.com/pwr/Solaar/issues/283 With the new documentation, released yesterday, I added support for it today, on a set of patches at: https://github.com/mchehab/Solaar/tree/mx_anywhere2-v3 With those patches, Solaar, in CLI, mode, shows the status of the high-res wheel: 11: HIRES WHEEL {2121} Multiplier: 8 Has invert Normal wheel motion Has ratchet switch Free wheel mode Low resolution mode HID notification And allows to toggle at the 3 possible switches: - Invert wheel movement; - Change to high-resolution mode - with makes the wheel to scroll 8 times faster; - Select between HID or HID++ notifications. It also generate an event when the ratchet button is clicked (changing from ratchet mode to freewheel). Solaar now handle those events using hiraw interface. When the notification is set to HID mode, evdev properly generates Wheel events: 1490181781.995144: event type EV_REL(0x02): REL_WHEEL (0x0002) value=-1 1490181781.995144: event type EV_SYN(0x00). 1490181782.211146: event type EV_REL(0x02): REL_WHEEL (0x0002) value=1 1490181782.211146: event type EV_SYN(0x00). But it doesn't generate events when ratchet switch button is pressed. When the notification is changed to HID++ mode, it also doesn't generate events. I suspect that the right thing to do would be to add a handler for it, probably at: drivers/hid/hid-logitech-hidpp.c On Solaar, with my patches, we can receive such messages via hidraw interface: HID++ wheel movement event: 07:37:22,846 DEBUG [ReceiverListener:hidraw1] logitech_receiver.base: (13) => r[11 03 0B00 01FFFF00000000000000000000000000] 07:37:22,847 INFO [ReceiverListener:hidraw1] logitech_receiver.notifications: <PairedDevice(3,404A,Anywhere MX 2)>: WHEEL: res: 0 periods: 1 delta V:-1 Ratchet event (generated on both HID and HID++ modes): 08:26:12,455 DEBUG [ReceiverListener:hidraw2] logitech_receiver.base: (13) => r[11 03 0B10 01000000000000000000000000000000] 08:26:12,456 INFO [ReceiverListener:hidraw2] logitech_receiver.notifications: <PairedDevice(3,404A,Anywhere MX 2)>: WHEEL: ratchet: 1 With regards to ratchet, it probably makes sense to query its state when the driver starts, as IMHO, it should work on a way similar to <CAPS LOCK>. Btw, are there any event already defined for ratchet mode? As I never touched on those HID drivers, could someone either add support for it or shed some light about what would be the proper way to add support for it? Thanks! Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
