grub2 and DSDT runtime load question

Altoid · 11-07-2016, 05:26 AM

Hello:

I've posted this question in a couple of other places but it seems no one wants to talk about it.

To the point:
In order to fix some ACPI issues in my setup (Sun Ultra 24 + Linux Mint 18 64bit) I've tried to load a custom dsdt file at run time.

As it was not working even though the modified dsdt file compiled with 0 errors, I tried loading the original (unmodified) one to see if it was some problem with grub2 loading of the file.

It did not work either.
It seems I may have a syntax problem. (?)

I have tried these two variants with the same result, a black screen with only Ctrl+Alt+Del as a solution:

1.
adding a kernel variable

Code:

acpi=/boot/dsdt.aml

Then

Code:

sudo update-grub2

which would declare it found the file and finish without issues.

2.
by means of a file in /etc/grub.d

Code:

#!/bin/sh -e

# Uncomment to load custom ACPI table
GRUB_CUSTOM_ACPI="/boot/dsdt.aml"

# DON'T MODIFY ANYTHING BELOW THIS LINE!

prefix=/usr
exec_prefix=${prefix}
libdir=${exec_prefix}/lib

. /usr/share/grub/grub-mkconfig_lib
#. ${libdir}/grub/grub-mkconfig_lib

# Load custom ACPI table
if [ x${GRUB_CUSTOM_ACPI} != x ] && [ -f ${GRUB_CUSTOM_ACPI} ] \
        && is_path_readable_by_grub ${GRUB_CUSTOM_ACPI}; then
    echo "Found custom ACPI table: ${GRUB_CUSTOM_ACPI}" >&2
    prepare_grub_to_access_device `${grub_probe} --target=device ${GRUB_CUSTOM_ACPI}` | sed -e "s/^/  /"
    cat << EOF
acpi (\$root)`make_system_path_relative_to_its_root ${GRUB_CUSTOM_ACPI}`
EOF
fi

and making it executable.

Code:

chmod +x /etc/grub.d/01_acpi

which would declare it found the file and finish without issues.

Q:
Why isn't this working?
It seems that grub just stops as it starts.
I have tried to find a syntax problem but (to me) it looks OK.

Any ideas?

Thanks in advance.

Note to Admin:
Please move to another forum if it does not belong here.

Elizine · 11-08-2016, 12:17 AM

Here's a solution -

Code:

chmod +x /etc/grub.d/01_acpi

This will tell GRUB to include the DSDT into its core.img (change GRUB_CUSTOM_ACPI to reflect the path to your .aml file). Next you will need a new boot image. If you use GRUB run:

Code:

grub-mkconfig -o /boot/grub/grub.cfg

Lastly, recreate your initrd

Code:

mkinitcpio -p linux

and reboot. Done!

Altoid · 11-09-2016, 11:52 AM

Hello:

Sorry for the delay in answering.

[QUOTE=Elizine;5628234]Here's a solution ...[/CODE]
I think this does not work with Mint 18 64bit.

This is what I am running:

Code:

~ $ uname -a
Linux 4.4.0-45-generic #66-Ubuntu SMP Wed Oct 19 14:12:37 UTC 2016 x86_64 GNU/Linux

This is what happens:

Code:

~ $ mkinitcpio -p linux
mkinitcpio: command not found

I don't see mkinitcpio anywhere in the file system.

Any ideas?

Thanks for your input.

A.