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Hibernation on Lenovo ThinkPad T14 Arch Linux

1. BIOS Setting: Enable Linux S3 Sleep

  1. Reboot and enter BIOS (Enter on Lenovo T14).
  2. Go to Power → Sleep.
  3. Set Sleep State to Linux S3.
  4. Save and exit.

2. Check Deep Sleep Support

cat /sys/power/mem_sleep

  • Example output: s2idle [deep]
  • deep is required for hibernation.

3. Create a Swap File

If your swap partition is as large as your RAM, this is not necessary.

For 16 GB RAM, a 16–18 GB swap file is recommended:

sudo fallocate -l 16G /swapfile sudo chmod 600 /swapfile sudo mkswap /swapfile sudo swapon /swapfile

Check it:

swapon --show

Make it permanent in /etc/fstab:

/swapfile none swap sw 0 0

4. Find Swap File Offset and Device

The kernel needs to know:

  1. Underlying device of the filesystem containing /swapfile:

df /swapfile

  • Example output:

Filesystem 1K-blocks Used Available Use% Mounted on /dev/nvme0n1p2 488281250 1234567 487000000 1% /

  • Here, the root device is /dev/nvme0n1p2.

  • Swap file offset (in 4 KiB blocks) using filefrag:

sudo filefrag -v /swapfile | head -n 4

  • Look at the physical offset of the first extent (column physical_offset of the first line).

  • Multiply by 4096 if your kernel boot parameter needs bytes, or use the number directly if it expects 4 KiB blocks.

  • Example: 5324800.

5. Configure Kernel Boot Parameters for Resume

When booting the kernel via EFI directly, you need:

resume=/dev/nvme0n1p2 resume_offset=5324800

  • resume= → the device containing your swap file.
  • resume_offset= → offset of the swap file.

Check current EFI entries:

sudo efibootmgr

  • Modify the entry to add the parameters:
efibootmgr \  
 -c \  
 -d /dev/nvme0n1 \  
 -p 1 \  
 -L "Arch Linux" \  
 -l '\vmlinuz-linux' \  
 -u "root=UUID=6c224d0d-80f2-4e70-925a-459b50344859 rw resume=UUID=6c224d0d-80f2-4e70-925a-459b50344859 resume_off  
set=5324800 initrd=\initramfs-linux.img"

- Replace 6c224d0d-80f2-4e70-925a-459b50344859 with the UUID of your root partition.

6. Test Hibernation

  1. Ensure swap is active:

swapon --show

  1. Trigger hibernation:

sudo systemctl hibernate

  • Laptop should save RAM to swap and power off.
  • On boot, it should resume your session.

  • It is pretty obvious if this worked.

  • Check logs:

journalctl | grep -i resume

7. Debugging Tips

Issue Check / Fix
Laptop doesn’t power off Confirm BIOS is Linux S3 and cat /sys/power/mem_sleep shows deep.
Resume fails Ensure resume= points to the correct device and resume_offset= matches swap file first extent.
Swap too small Swap ≥ RAM (16 GB → 16–18 GB).
Kernel doesn’t recognize swap Re-run mkswap /swapfile and swapon /swapfile.

This ensures the swap file is hibernate-ready even without a dedicated swap partition.