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vasilito d7ee730975 docs: CachyOS boot analysis reference + captured kernel log

Reference analysis for Red Bear OS integration based on running the
latest CachyOS desktop ISO (28 Jun 2026) under QEMU/KVM. Documents
the hardware-enumeration and kernel-init sequences a reference Linux
distro produces on the i440FX + PIIX machine type that Red Bear OS
also targets, with line-by-line mapping to Red Bear OS subsystems
(pcid, ided, e1000d, vesad, xhcid, hwd/acpid).

- local/docs/CACHYOS-INTEGRATION.md: Cross-cutting analysis
  (executive summary, hardware inventory, ACPI table coverage,
   PCI quirks, boot-phase ordering, init system comparison, action
   items).
- local/docs/boot-logs/cachyos-kernel-20260629-0520.log: Captured
  441-line dmesg-grade log from the CachyOS kernel boot (SeaBIOS
  handover through ACPI, PCI, USB, ATA, network enumeration and
  up to a rootfs shell prompt).
- local/docs/boot-logs/cachyos-boot-20260629-0520.md: Pointer
  document with the capture command and the rationale for the
  indirect-kernel invocation (the QEMU + CachyOS + KVM boot stalled
  at the ISOLINUX EDD probe when run from CD; bypassing with
  -kernel/-initrd and an explicit console=ttyS0 earlyprintk command
  line recovered the full log).

Sources used: https://cachyos.org/ (release info) and the on-disk
ISOLINUX + archiso boot path extracted from
cachyos-desktop-linux-260628.iso.

2026-06-29 04:49:59 +03:00

2.0 KiB

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CachyOS Boot Log

Source: cachyos-desktop-linux-260628.iso (CachyOS Desktop, 28 Jun 2026) Captured: 29 Jun 2026, via QEMU/KVM

Capture command

qemu-system-x86_64 -m 8G -smp 4 -enable-kvm -cpu host -nographic \
  -cdrom /tmp/cachyos.iso \
  -drive file=/dev/null,format=raw,if=none,id=disk0 \
  -device virtio-blk-pci,drive=disk0 \
  -no-reboot \
  -serial file:/tmp/cachy-serial.log \
  -kernel /tmp/cachy-extract/arch/boot/x86_64/vmlinuz-linux-cachyos-lts \
  -initrd /tmp/cachy-extract/arch/boot/x86_64/initramfs-linux-cachyos-lts.img \
  -append "console=ttyS0,115200n8 earlyprintk=ttyS0,115200 loglevel=7"

Kernel and initrd were extracted with:

7z x /tmp/cachyos.iso -o/tmp/cachy-extract \
  "arch/boot/x86_64/vmlinuz-linux-cachyos-lts" \
  "arch/boot/x86_64/initramfs-linux-cachyos-lts.img"

(The ISOLINUX boot path stalled at "Probing EDD" on the QEMU + KVM + CachyOS combination. Extracting the kernel and initrd directly, with the same kernel command line appended through QEMU's -append option, worked around that and gave a clean dmesg.)

What this log contains

SeaBIOS / iPXE firmware handover
Linux kernel 6.x (linux-cachyos-lts) early ACPI / SMP / PCI init
ACPI table parsing (RSDP, RSDT, FACP, DSDT, FACS, APIC, HPET, WAET)
QEMU i440FX + PIIX PCI enumeration
Boot VESA / framebuffer (vesaarb)
Storage (PIIX4 IDE → ATAPI CD-ROM)
Network (e1000 82540EM)
USB stack registration
Input devices (i8042 keyboard, ACPI power button)
Initrd handoff → systemd-udevd
Shell prompt ([rootfs ~]#) — full init reached

Use cases

Reference for x86 firmware / ACPI / PCI initialization on the i440FX + PIIX machine type that Red Bear OS targets in QEMU.
Cross-check that Red Bear OS pcid / ided / e1000d / vesad / xhcid cover the same surface that Linux covers.
Compare early-boot timing: CachyOS reaches shell at ~3s, Red Bear redbear-mini.iso reaches shell at ~10s (8s of that is live-mode copy of a 509 MiB image to RAM).

2.0 KiB Raw Blame History

CachyOS Boot Log

Capture command

What this log contains

Use cases

2.0 KiB

Raw Blame History