rob thijssen
3762f13d8b
I had this wrong. The claim that accelerated graphics works on the firmware Fedora ships does not survive contact with the device tree. Fedora does package an sdm845/a630_zap.mbn, which is what led me astray, but that is the generic Snapdragon 845 zap shader. The C630's node in sdm850-lenovo-yoga-c630.dts names qcom/sdm850/LENOVO/81JL/qcdxkmsuc850.mbn specifically — model-signed, present only in the machine's Windows partition. Until it is supplied the display is unaccelerated. Also add qcslpi850.mbn and qcvss850.mbn, which were missing entirely, and attribute the sensor hub to slpi_pas rather than cdsp_pas. The list is now every firmware-name property in the mainline device tree rather than a recollection of forum posts, so it should be complete: eight files, not five. WiFi and Bluetooth are unaffected — ath10k WCN3990 including wlanmdsp.mbn is genuinely redistributable and genuinely shipped. Add a section on locating the blobs on an old backup, for the case where Windows is long gone from the machine. Only comments changed in config/packages/base.pkgs, so the package set hashes identically and the staged base stays valid. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01XWRjNJMistCy6ngXH5aJLS
133 lines
6.0 KiB
Markdown
133 lines
6.0 KiB
Markdown
# Fedora for the Lenovo Yoga C630 13Q50
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Builds a ready-to-write Fedora aarch64 disk image for the Lenovo Yoga C630
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(model 81JL, Qualcomm SDM850), using Gitea Actions.
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The approach is borrowed from [aarch64-laptops/build][aal], but the heavy
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lifting that project had to do in 2019 is now unnecessary: mainline Linux has
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carried `sdm850-lenovo-yoga-c630.dts` since 5.5, and Fedora ships it in
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`kernel-core`. There is no kernel to patch and no GRUB to compile. What is left
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is assembling a disk image that boots on hardware whose firmware hands Linux no
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device tree.
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[aal]: https://github.com/aarch64-laptops/build
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## What you get
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`output/fedora-44-<variant>-lenovo-yoga-c630-<date>-<ref>.img.zst` — a GPT disk
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image with an ESP, a `/boot` partition and an ext4 root. Decompress, write it to
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a USB stick or microSD card, and boot. The root filesystem grows to fill the
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medium on first boot.
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Two variants:
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| Variant | Size | Contents |
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|---------------|-------|----------------------------------------------|
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| `minimal` | 8 GiB | Console, sshd, and enough tools to debug the machine |
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| `workstation` | 16 GiB| GNOME desktop |
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Default login is `fedora` / `fedora`, and the password must be changed at first
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login. Root is locked.
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## Hardware status
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| Works out of the box | Needs firmware from Windows | Not supported |
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|---------------------------------|-----------------------------|---------------|
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| UFS storage, USB, keyboard, touchpad, touchscreen | Graphics (Adreno 630 zap shader) | LTE modem |
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| WiFi + Bluetooth (ath10k WCN3990) | Audio | |
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| Battery and charging | Sensor hub — lid switch, accelerometer, auto-rotate | |
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| Display (unaccelerated) | Hardware video decode (venus) | |
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Fedora ships everything Qualcomm permits to be redistributed, which covers
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WiFi and Bluetooth outright. Graphics is the awkward case: the generic Adreno
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pieces (`a630_gmu.bin`, `a630_sqe.fw`) are packaged, but the C630's device tree
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asks for a **model-signed** zap shader, `qcdxkmsuc850.mbn`, which exists only in
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your machine's Windows partition — Fedora's generic `sdm845/a630_zap.mbn` is not
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what this device requests. Audio, sensors and video decode are the same story.
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Run `sudo c630-firmware` once after installing — see
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[docs/firmware.md](docs/firmware.md) for the full list and a manual fallback.
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## Building
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CI does this on every push to `main`. To run it yourself:
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```sh
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./build/build-image.sh --variant minimal
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```
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You need `podman` and, on an x86_64 host, aarch64 emulation:
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```sh
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sudo dnf install -y qemu-user-static-aarch64
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sudo systemctl restart systemd-binfmt
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```
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`build/build-image.sh` runs on the host and only sets up the container.
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`build/stage2.sh` runs inside an aarch64 Fedora container and does everything
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else: `dnf --installroot`, the overlay, dracut, and the disk assembly. It builds
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filesystems from directory trees with `mke2fs -d` and `mcopy` rather than
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mounting loop devices, so it does not need `/dev/loop-control` — which CI
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runners generally will not hand out.
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### Iterating
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Every aarch64 binary runs under emulation, and the `dnf` transaction is
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essentially all of the cost — 500-odd packages' worth of rpm scriptlets for
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`minimal`, four times that for `workstation`. Everything after it takes
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minutes. Since getting this machine to boot will take a few attempts, the build
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is arranged so you only pay that once:
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- The post-`dnf` root filesystem is staged under `<work>/base`, keyed on a hash
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of the package lists, release and variant. Editing `config/device.env`,
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`overlay/`, or the bootloader config reuses it. Editing `config/packages/`
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invalidates it automatically.
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- The working copy is made with `cp --reflink=auto`, so on btrfs or xfs it is
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a copy-on-write clone rather than a real copy.
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- Downloaded rpms live in `.cache/dnf`, outside the staged tree, so even
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`--fresh` re-runs the scriptlets without re-downloading.
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In practice a kernel-command-line change rebuilds in a few minutes.
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```sh
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./build/build-image.sh --variant minimal # reuses the staged base
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./build/build-image.sh --variant minimal --fresh # forces a reinstall
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./build/build-image.sh --variant minimal --keep-rootfs # keep the tree to poke at
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```
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CI points `--work` and `--cache` at `/var/tmp/c630-build` so both survive
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between jobs. That is per-runner, so the first build on a given runner is cold.
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The build container defaults to `git.lair.cafe/gongfoo/build-fedora-44-aarch64`,
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which ships the assembly tooling so it does not have to be installed under
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emulation on every run. If that image is not reachable the build falls back to
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stock Fedora and installs the tooling itself — slower, but it works.
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## Repository layout
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```
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config/device.env C630 parameters: DTB path, kernel command line, geometry
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config/packages/*.pkgs Package lists — base plus one file per variant
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overlay/ Files copied into the root filesystem (*.in are templated)
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build/build-image.sh Host driver: emulation checks, podman invocation
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build/stage2.sh The actual build, inside an aarch64 container
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firmware/local/ Optional drop-in for firmware you extracted yourself (gitignored)
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.gitea/workflows/ CI
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docs/ Installation, firmware, runner setup
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```
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## Documentation
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- [docs/install.md](docs/install.md) — writing the image and booting the laptop
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- [docs/firmware.md](docs/firmware.md) — what needs extracting from Windows and why
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- [docs/runner-setup.md](docs/runner-setup.md) — one-time Gitea runner preparation
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## Caveats
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The build has not yet been confirmed to boot on real hardware. The device tree,
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kernel command line and firmware layout are taken from Fedora's Snapdragon WoA
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documentation and the aarch64-laptops project; the parts specific to the C630's
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older SDM850 are reasoned from those rather than tested. Expect to spend a boot
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or two adjusting `DEVICE_CMDLINE` in `config/device.env`. Findings belong in
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this README.
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