yserver

A modern X11 server written from scratch in Rust.

Info about the project is in README.md Current status is in docs/status.md and should be kept up to date focus is on yserver (KMS) now

Instructions

• it's fine not to use clippy pedantic in this repo but DO use regular clippy
• before committing, run clippy exactly as CI does: cargo clippy --all-targets -- -D warnings. CI fails on any warning, and --all-targets lints test code too — a crate-scoped or non---all-targets run misses lints in tests (e.g. needless_range_loop) and they only surface on GH.
• use cargo +nightly fmt for formatting
• when adding or changing ioctls, watch for libc linuxisms: request-type aliases like libc::Ioctl are not portable across all supported targets, and musl/FreeBSD have regressed here before. Keep ioctl request typing/buildability valid on Linux glibc, Linux musl, and FreeBSD.
• design docs (specs) go in docs/superpowers/specs
• impl plans go in docs/superpowers/plans
• work on feature branch for phases
• squash merge when ready (ask confirmation)
• Spec compliance is the goal, but if Xorg deviates from spec (unlikely), we need to follow Xorg, clients are tested for 40+ years on Xorg.

environment

• you are most likely running in a bwrap sandbox, if you see /home/jos/realhome, you are.
• the project dir is rw mounted
• in /home/jos/Projects/xserver/hw/kdrive/ephyr/ you can find the source to Xephyr for reference
• in /home/jos/Projects/xserver/hw/xnest/ you can find the sources to Xnest for reference
• to test you can run ynest with RUST_LOG=debug, capture its output
• x11trace is available if you want to trace how Xephyr/Xnest does things, x11trace always needs -n flag

yserver

A modern X11 server written from scratch in Rust.

The goal is not to clone Xorg. It is to provide a practical X11 server that runs real desktop environments, window managers, and applications on modern Linux while dropping legacy baggage (non-TrueColor visuals, indirect GLX, the DDX driver ABI, endian-swapped clients, and so on).

See docs/high-level-design.md for the full design and scope.

Name

The yserver name is the 'working' name as it was the first idea that popped into my head when starting the project. But there are multiple projects on GitHub with this name (but none for X11 servers), the name is subject to change. Not a priority now.

Status

yserver (standalone DRM/KMS) can now run full MATE/XFCE/Cinnamon desktops. Other tested window managers include FVWM3, e16 and wmaker.

We support the following extensions:

• BIG-REQUESTS
• Composite
• DAMAGE
• DPMS
• DRI3
• GLX
• Generic Event Extension
• MIT-SCREEN-SAVER
• MIT-SHM
• Present
• RANDR
• RENDER
• SHAPE
• SYNC
• X-Resource
• XFIXES
• XINERAMA
• XInputExtension
• XC-MISC
• XFree86-VidModeExtension
• XKEYBOARD
• XTEST

GLX_OML_sync_control

Mesa implements glXGetMscRateOML() on the client side by reading the current mode through XFree86-VidModeExtension. Yserver implements Xorg's read surface with the correct legacy/v2 wire layouts and the selected output's real DRM/RANDR timing, monitor identity, programmable clock capability, viewport and gamma ramp. This lets Mesa and ANGLE-based Flatpak clients derive the display MSC rate while other VidMode readers see data consistent with RANDR instead of unexpected BadRequest errors.

VidMode remains deliberately read-only because RANDR owns display configuration. GetPermissions advertises only XF86VM_READ_PERMISSION, and known mode/gamma writes fail with VidMode's ClientNotLocal error — the same coherent fallback branch Xorg exposes to a client without write permission. Yserver clients are physically local Unix-socket peers, so this is an explicit server policy rather than a claim that they are remote.

GLX_EXT_texture_from_pixmap

Implemented and tested on AMD, intel, Asahi and Qualcomm. It can NOT (read: NEVER) work on nvidia proprietary driver, and on the only nvidia card I have (GTX 1050), the nouveau driver can not even bring up Xorg. Nouveau may work on other cards, but untested.

Recent work

• starty launcher (startx-style: display number picking, MIT-MAGIC-COOKIE-1, session teardown)
• Present completions paced to the vblank, and the Present 1.4 acquire timeline honored (fixes free-running clients, fullscreen video, Plasma's spinner)
• keyboard layout switching: stale per-key overrides cleared and a legacy MappingNotify broadcast, so clients pick up the new layout (@azytar)
• FreeColors dispatched instead of failing with BadRequest (Tk compatibility) (@erpalma)
• GLX pbuffers, backed by a real GPU pixmap — Chrome and Steam now get GPU acceleration
• scanout buffers allocated via GBM and imported into Vulkan (wider driver/modifier coverage)
• yserver is now truly idle when nothing happens
• core-loop fairness and backpressure
• RANDR output properties, read and write (minors 12/13/14)
• RANDR output identity passthrough: EDID, EDID_DATA, ConnectorType
• RANDR fractional refresh rates from real kernel mode timings
• Xorg-compatible output names (HDMI-1, not HDMI-A-1)
• X-Resource client accounting with LocalClientPID in QueryClientIds
• per-device libinput settings (mice and touchpads) actually apply
• XI1 feedback controls, resolution control, real event selections
• pointer motion history (GetMotionEvents)
• XI2: relative RawMotion deltas, scroll-stop on finger-lift, implicit pointer grabs, unified freeze state
• XTEST cursor comparison
• RENDER: full standard PictOp family, a8-mask destinations for CompositeGlyphs, ClipByChildren parity for Composite/Glyphs/Traps/Tris
• perf: glyph rendering batched into one instanced draw per text run
• cursor recoloring, and depth-1 wire bitmaps for XCreatePixmapCursor
• XKB group state and GetMap component filtering (@AprilGrimoire)
• CopyArea source resolution simplified (@AprilGrimoire)
• stable-toolchain build fixed on Ubuntu 26.04 (@erpalma)
• Direct-only seat model (libseat dependency dropped)
• much better responsiveness on NVIDIA GPUs
• newly working apps: Steam (WebGL), ImageMagick import region-select, KDE Plasma RandR resize + ARGB popups (@erpalma), fullscreen games/video under Cinnamon
• newly tested and fixed desktops: plasma X11 (sonic DE)
• binary releases for Fedora/Debian/Ubuntu/Alpine

Previously

• FreeBSD now works
• Display hotplug now works
• xauth support (no xhost ACL support - not needed as we're unix socket only)
• XINERAMA support
• RANDR gamma correction (redshift)
• direct mode VT switch
• XKB runtime layout change
• LEDs driven from XKB state
• XFIXES pointer barriers
• XC-MISC XID recycling
• musl (Alpine) build working
• newly tested and fixed desktops: bspwm/sxhkd, enlightenment 0.27, icewm, awesome, openbox, picom, blackbox

Demo

With TFP implemented, we now support compiz, demo here:

https://github.com/user-attachments/assets/dc266c55-e9ee-4649-a0c4-be3db2526713

Tested WMs/desktops

yserver has been tested end-to-end against the following WMs/desktops:

• Cinnamon
• MATE
• XFCE
• FVWM3
• sonic (KDE plasma X11 fork)
• wmaker
• openbox
• awesome
• picom
• compiz
• icewm
• blackbox
• bspwm/sxhkd
• i3/fastcompmgr
• enlightenment e16 + e27

Hardware tested

• AMD — Ryzen 9 6900HX (Rembrandt, RDNA2, RADV); i9 13900k + RX580 (Polaris/GCN4, RADV).
• Intel — i5-7200U (Kaby Lake, ANV) iGPU.
• NVIDIA — i5 6500 with GTX 1050 (proprietary driver).
• Snapdragon X1 X1E80100 (Adreno X1, Turnip).
• Apple M1 MBA, M2 MBP on Asahi Linux (apple-drm KMS + asahi GPU, Mesa AGX-V).
• Virtual — virtio-gpu inside virtme-ng (Venus passthrough).

FreeBSD was tested on the i9 (GhostBSD).

Installation and setup

Full instructions — dependencies per distro, device access, display manager and console startup, key bindings, troubleshooting and packaging — are in docs/setup.md, also installed to $prefix/share/doc/yserver/setup.md.

The short version, from a source checkout:

just install-local                   # builds and installs to /usr/local
sudo usermod -aG video,input $USER   # then log out and back in

Then switch to a free console and run starty. yserver drives atomic KMS directly with no seat manager, so it needs access to /dev/dri/* and /dev/input/event* and a working Vulkan driver.

Packages

• Arch (and derivatives): yserver and yserver-git on the AUR
• Fedora, debian, ubuntu and alpine packages in Releases

The release files are loose packages, not repositories, so install them by path:

sudo dnf install ./yserver-*.rpm
sudo apt install ./yserver_*.deb
sudo apk add --allow-untrusted ./yserver-*.apk   # signed with a per-build key

See also yserver(1) and starty(1).

Regression coverage with xts5 and rendercheck

We run the X.Org X Test Suite (xts5) against yserver to gauge protocol completeness.

Latest pass numbers per scenario live in docs/test-status.md.

To run XTS yourself, you need to install the following extra packages:

sudo pacman -S --needed autogen automake autoconf make xtrans xterm xorg-xset xorg-fonts-misc xorg-xdpyinfo xorg-bdftopcf xorg-mkfontscale xorg-util-macros

Then clone https://gitlab.freedesktop.org/xorg/test/xts.git next to the yserver repo. Build it with:

./autogen.sh
make

Switch to a free VT and use just xts-yserver-hw. It takes about 50 minutes, don't touch mouse/kb, xts drives the mouse on some tests.

Contributing

Contributions are welcome — see CONTRIBUTING.md for the toolchain, the checks CI runs, and the signed-commit requirement.

License

This project is licensed under the MIT license. Please check LICENSE.