Commit a476e183 authored by Benoit Rat's avatar Benoit Rat

doc: review the section to set specific kernel (downgrade)

Fix markdown format
parent 88d088c1
......@@ -1677,21 +1677,35 @@ make
You should finally obtain the bitstream to import in your [FMC] driver folder.
Set Previous Kernel Version
Set Specific Kernel Version
===========================
This chapter describes how to set a previous kernel version when you have problems during the installation with the latest kernel versions.
This chapter describes how to set a force loading a specific (previous) kernel version if you have problems while compiling/loading the wr-starting-kit
drivers with newest/latest kernel[^ubuntultskernel].
Find the **$menuentry_id_option** for the submenu
> ***Note:*** We recommand to fix your kernel to `4.18.xxx`, as it has been the one that have reported less error during development.
[^ubuntultskernel]: We usually support the current Ubuntu LTS at the moment of writing this document, however during the LTS cycle there are
minor release that might contains a newer kernel incompatible with our drivers: <https://wiki.ubuntu.com/Kernel/Support>.
Find the ID of the submenu
-------------------------------------------------
~~~~~~{.bash}
We first need to obtain the `$menuentry_id_option` for the current submenu:
~~~~~~
>:$ grep submenu /boot/grub/grub.cfg
submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
~~~~~~~~~~~
Show available kernel entries
List available kernel entries
-----------------------
~~~~~~{.bash}
>:$ grep -A100 submenu /boot/grub/grub.cfg |grep menuentry
~~~~~~
>:$ grep -A100 submenu /boot/grub/grub.cfg | grep menuentry
submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
menuentry 'Ubuntu, with Linux 5.0.0-32-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.0.0-32-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
menuentry 'Ubuntu, with Linux 5.0.0-32-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-5.0.0-32-generic-recovery-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
......@@ -1699,23 +1713,28 @@ submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-54
menuentry 'Ubuntu, with Linux 4.18.0-17-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.18.0-17-generic-recovery-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
menuentry 'Ubuntu, with Linux 4.15.0-46-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-46-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
menuentry 'Ubuntu, with Linux 4.15.0-46-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.15.0-46-generic-recovery-541c21ee-e687-4a1e-9f8c-c1b6285694da' {
~~~~~~~~~~
~~~~~~~~~~~
Create the default menu entry
-----------------------------
The parent entry id for Advanced options in this case is **gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da**
Choose the entry for the kernel you want to use. For example, **gnulinux-4.18.0-17-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da**
The parent entry id for Advanced options in this case is `gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da`
Choose the entry for the kernel you want to use. For example, `gnulinux-4.18.0-17-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da`
Conacate both entries with `>` The result should be like:
`"gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da > gnulinux-4.18.0-17-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da"`
Conacate both entries with >. The result should be like:
**"gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da > gnulinux-4.18.0-17-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da"**
Edit Grub
----------
Edit the file **/etc/default/grub** and replace **GRUB_DEFAULT** with the previously created entry. The file would look like
~~~~~~{.bash}
Edit the file `/etc/default/grub` and replace `GRUB_DEFAULT` with the previously created entry. The file would look like
~~~~~~{.sh}
GRUB_DEFAULT="gnulinux-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da > gnulinux-4.18.0-17-generic-advanced-541c21ee-e687-4a1e-9f8c-c1b6285694da"
#GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=10
......@@ -1726,7 +1745,8 @@ GRUB_CMDLINE_LINUX=""
Update Grub and Reboot
----------------------
~~~~~~{.bash}
~~~~~~{.sh}
>:$ sudo update-grub
>:$ sudo reboot
~~~~~~~~~~~
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment