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Linux Graphics

ToDo: Contribute (some of) this as e.g. https://wiki.archlinux.org/title/Wayland ?

Introduction & Overview

Wayland (Wikipedia, Homepage, ArchLinux) is the modern successor to the venerable X11.

It uses / builds on top of Linux Kernel Mode Setting (KMS) (Kernel doc, freedesktop.org, Wikipedia, ArchLinux), which normall should just work - unless you want to start it early:

$ cat /proc/fb
0 i915drmfb

$ sudo dmesg | grep drm
[    0.342936] ACPI: bus type drm_connector registered
[    1.752959] systemd[1]: Starting Load Kernel Module drm...
[    1.790955] systemd[1]: modprobe@drm.service: Deactivated successfully.
[    1.791179] systemd[1]: Finished Load Kernel Module drm.
[    1.791560] audit: type=1130 audit(1665849003.912:5): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=modprobe@drm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[    1.791593] audit: type=1131 audit(1665849003.912:6): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=modprobe@drm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[    3.393187] [drm] Initialized i915 1.6.0 20201103 for 0000:00:02.0 on minor 0
[    3.410130] fbcon: i915drmfb (fb0) is primary device
[    4.563095] i915 0000:00:02.0: [drm] fb0: i915drmfb frame buffer device

Wayland is a protocol. Wayland packages just contain shared libraries, and does not contain or have an no dependencies to any executables that "do" anything (see Package Contents).

Wayland's clients are apps that want to draw pixels on the screen.

The Wayland server, also known as "compositor" actually draws those pixels. There are a number of such Wayland compositors (ArchLinux, Wikipedia).

Weston is one such "compositor"; let's install and try it out, on the console not via SSH: (Note how the weston package depends e.g. on wayland, libdrm, mesa, libpng, libjpeg, libwebp, cairo, freetype, pango or pipewire for sound as well as libinput and even libx11 and more.)

sudo pacman -S weston

Click the terminal icon in the upper-left hand corner of the screen, and from there launch:

weston-flower

You can even launch Weston within Weston! ;-) Ctrl+Alt+Backspace quits Weston.

Firefox seems to work under Wayland; about:support should show wayland instead of x11.

Chromium currently in v106 works (under Weston) with --ozone-platform=wayland (--enable-features=UseOzonePlatform doesn't seem to be required; --ozone-platform-hint=auto doesn't work); otherwise it fails: missing X server or $DISPLAY.

Kitty is a great alternative to weston-terminal, but it initially fails to start with an obscure error under Weston. But after installing the alternative foot terminal, and (ToDo unclear...) the alternative Wayland compositor Sway, interestingly Kitty suddenly works under Sway:

sudo pacman -S noto-fonts sway foot
sway

Windows+Return opens foot terminal, Windows+Shift+e quits Sway; this cheatsheet has more.

ToDo: Customize Sway with correct keyboard, Kitty instead of Foot on Windows+Return, a 24h instead of 12h clock, automatically opening browser and terminal, etc. (Or just forget about Sway and only use Weston? If Kitty works!)

PS: Could also support Application Launchers via i3 syntax, or (better) via standard freedesktop.org .desktop files, e.g. using https://github.com/Biont/sway-launcher-desktop; but who really needs that, anyways.

Display Managers

ToDo: https://wiki.archlinux.org/title/Wayland#Display_managers, but... what's the point, what does one really need that for? ;-)

Videos

VLC should let us watches videos:

sudo pacman -S yt-dlp qt5-wayland vlc
yt-dlp "https://www.youtube.com/watch?v=PUn4n-nGraM"
vlc smurfs.mp4

But this doesn't quite work, until audio is set-up.

Hardware Acceleration

ToDo: https://wiki.archlinux.org/title/Hardware_video_acceleration

Modern Monitors

dmesg -w -d -t -H -x will typically show a lot of interesting info and debug (but should not have any err) pci* and USB related messages when a modern (non-VGA) monitor is plugged in via a USB-C to USB-C, or USB-C to HDMI, or USB-C to DisplayPort (but not HDMI to HDMI; not sure about DisplayPort to DisplayPort).

The following commands (from here) provide further details:

 sudo i2cdetect -l
 sudo i2cdetect 8

 ddcutil -h
 sudo ddcutil detect
 sudo ddcutil detect -v
 sudo ddcutil --bus 8 capabilities
 sudo ddcutil getvcp known --bus 8

Hacking

ToDo: Hack a bunch of "hello, world" kind of graphical demos...

  • Start with something drawing pixels on KMS?
  • Then ideally initially only using just libwayland-client's wl_* functions.
  • Then with Cairo or OpenGL?
  • Then subsequently use e.g. GTK as GUI library