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I have a new Thinkpad X1 Yoga 2018 which requires a patch to the ACPI DSDT to make suspend-to-RAM work. I've built a patched DSDT following these instructions, and created a CPIO archive called acpi_override.

How do I customize the configuration in /etc/grub.d or /etc/initramfs-tools (or elsewhere) to have this loaded along with Kubuntu's initrd? I was looking for a line where initrd [...] was emitted in /etc/grub.d/10_linux but it seems things have been rearranged for this release.

josePhoenix
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2 Answers2

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There ended up being a different way to accomplish the same thing.

  1. Extract the CPIO file: cpio --extract < ./acpi_override
  2. Copy the result to /boot: cp kernel/firmware/acpi/dsdt.aml /boot/fixed_dsdt.aml
  3. Create or update /boot/grub/custom.cfg to contain acpi /fixed_dsdt.aml

Since /boot/grub/custom.cfg isn't managed by apt, this should persist.

Note: If you're not confident you've got the right DSDT, you could end up in a reboot loop. You could instead manually edit the grub.cfg and add the acpi /fixed_dsdt.aml line inside of a boot entry. That way if grub tries to process it and fails, it will do so only after selecting the boot entry (not before showing the menu). Once you are confident that it all works, you can move your edits to custom.cfg.

josePhoenix
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This approach was what worked for me using (K)Ubuntu 18.04 on a 6th gen X1 carbon. The use of "initrd /boot/acpi_override /boot/initrd.img-4.14.0-20-generic" in the grub.cfg did not load the configuration, but removing "/boot/acpi_override" from this line and loading the .aml file on its separate line in grub.cfg now shows S3 as a supported power mode in dmesg and "s2idle [deep]" in /sys/power/mem_sleep.

Topher
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