Sorry, another set of questions - seems like I am a bit dense. On Thu, 27 Oct 2022 at 11:44, Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> wrote: > It's just Logitech's common HID protocol. The advantage is that if > Logitech reuses the feature on a different hardware, we won't have to > implement anything new in the kernel. Started implementing some illumination code but will take a while until I figure out the driver I think. > But from where you are now, you should probably be able to implement > the basic on/off feature by looking at the function 0x1000 in the > hid-logitech-hidpp code: > - you need define a few macros for your functionality (the class, the > commands, the events) So my approach would be to identify the GLOW device and then at some later point create the illumination state and from there only handle common illumination. > - you need to add a hook in connect_event to register the led class > device that will hook on to the actual LED of the device I did read all the LED specs/headers that I could find and from what I have seen all you can currently do with this interface is control brightness. There seems to be no way of controlling the Color temperature, though. So either this then would have to be exposed as a special device or get handled entirely in userspace. The latter seems to work against "implementing illumination handling once in driver and reusing it". > [0] https://pwr-solaar.github.io/Solaar > [1] https://github.com/pwr-Solaar/Solaar/blob/master/docs/hidpp-documentation.txt Thanks. Never would have found the specs on my own. That said - I read x1990 spec and tried to access getIllumination from userspace. The spec seems a bit vague for my limited experience level. For example I have not yet figured out what the communication (bytes) difference between _getIllumination()_ and _illuminationChangedEvent_ is. What seems to work is accessing events: So I tried: ```c #define LONG_REPORT_ID 0x11 struct hiddev_usage_ref_multi multi; memset(&multi, 0, sizeof(multi)); multi.uref.report_type = HID_REPORT_TYPE_INPUT; multi.uref.report_id = LONG_REPORT_ID; multi.uref.field_index = 0x0; multi.uref.usage_index = 0x03; multi.uref.usage_code = 0xff430002; multi.num_values = 1; if (ioctl(fd, HIDIOCGUSAGES, &multi) < 0) { perror("HIDIOCGUSAGES getIllumination"); return -11; } printf("VALUE: %0x\n", multi.values[0]); ``` Which seems to report the illumination state until I press another hardware button. So this seems to access the last event, which seems to be _illuminationChangedEvent_ in my case. No idea currently how to get _getIllumination_ to work. Cheers Andreas
