Hi,
Am 19.01.24 um 21:15 schrieb Pavel Machek:
Hi!
2. Implement per-key keyboards as auxdisplay
- Pro:
- Already has a concept for led positions
- Is conceptually closer to "multiple leds forming a singular entity"
- Con:
- No preexisting UPower support
- No concept for special hardware lightning modes
- No support for arbitrary led outlines yet (e.g. ISO style enter-key)
Please do this one.
Ok, so based on the discussion so far and Pavel's feedback lets try to
design a custom userspace API for this. I do not believe that auxdisplay
is a good fit because:
Ok, so lets call this a "display". These days, framebuffers and drm
handles displays. My proposal is to use similar API as other displays.
So my proposal would be an ioctl interface (ioctl only no r/w)
using /dev/rgbkbd0 /dev/rgbkdb1, etc. registered as a misc chardev.
For per key controllable rgb LEDs we need to discuss a coordinate
system. I propose using a fixed size of 16 rows of 64 keys,
so 64x16 in standard WxH notation.
And then storing RGB in separate bytes, so userspace will then
always send a buffer of 192 bytes per line (64x3) x 14 rows
= 3072 bytes. With the kernel driver ignoring parts of
the buffer where there are no actual keys.
That's really really weird interface. If you are doing RGB888 64x14,
lets make it a ... display? :-).
ioctl always sending 3072 bytes is really a hack.
Small displays exist and are quite common, surely we'd handle this as
a display:
https://pajenicko.cz/displeje/graficky-oled-displej-0-66-64x48-i2c-bily-wemos-d1-mini
It is 64x48.
And then there's this:
https://pajenicko.cz/displeje/maticovy-8x8-led-displej-s-radicem-max7219
and this:
https://pajenicko.cz/displeje/maticovy-8x32-led-displej-s-radicem-max7219
One of them is 8x8.
Surely those should be displays, too?
But what about a light bar with, lets say, 3 zones. Is that a 3x1 display?
And what about a mouse having lit mousebuttons and a single led light bar at the
wrist: a 2x2 display, but one is thin but long and one is not used?
Regards,
Werner
And yes, we'd probably want some extra ioctls on top, for example to
map from input device to this and back, and maybe for various effects,
too. And yes, I realize that display with holes in it and with some
pixels bigger than others is weird, but it still looks like a display
to me. (And phones have high-res displays with rounded corners and
holes in them, so... we'll need to deal with weird displays anyway).
Best regards,
Pavel
