Making Buntu >= 12.10 work on a Pentium M-CPU without PAE.

[7bit]

For example a ThinkPad t40 or other models from that era with this Pentium-M CPU?

ONLY if you can afford to make it unbootable (and know how to restore it back to a working Precise) please tell me if this works:

0) (X|L|U)buntu precise is installed and running
1) download this http://paste.ubuntu.com/1622104/
Edit: improved version: http://paste.ubuntu.com/1629628/
Edit2: I have made a deb package, see post #12: http://ubuntuforums.org/showpost.php...9&postcount=12
2) make it executable and execute it as root (sudo)
3) cat /proc/cpuinfo and verify that it now contains the pae flag.

4) sudo update-manager
5) upgrade the entire system to 12.10

6.) Did it install the 3.5 kernel without errors, does it still boot (with that kernel), are there any broken/unconfigured packages regarding the kernel?

[tgalati4]

I have a T43p (2006) vintage that I plan on upgrading from Jaunty, but I have to copy data off of it before I upgrade, so it will be a few days.

What is the purpose of this test? I thought most Pentium-M's supported PAE, but there might be a few early-production chips that don't.

I plan on either doing a clean install or adding a partition and making it dual boot. I have a 320GB drive, so I have some room to add another partition.

[7bit]

I have a T43p (2006) vintage that I plan on upgrading from Jaunty, but I have to copy data off of it before I upgrade, so it will be a few days.

What is the purpose of this test? I thought most Pentium-M's supported PAE, but there might be a few early-production chips that don't.

I plan on either doing a clean install or adding a partition and making it dual boot. I have a 320GB drive, so I have some room to add another partition.

if there is no pae flag in your /proc/cpuinfo then the deb package for the new kernel images (Quantal and later) will simply refuse to install (and leave the entire package system in en inconsistent state) although at least *some* of these Pentium-M would perfectly run these new kernels if it *would* be possible to install them. The purpose of this script is to patch /proc/cpuinfo to trick the kernel .deb install script into thinking it will be installed on a compatible CPU.

If you do a cat /proc/cpuinfo and don't find any mention of "pae" in the flags then it will probably refuse to boot from the 12.10 install CD and also for 12.04 there are only a few (Xubuntu, Lubuntu) CD images that allow to boot. Again this is not the fault of the kernel, in this case it is the bootloader of the CD that will check the CPU capabilities and simply refuse to even try to boot the kernel anyways!

This means the problem is twofold:
* apt-get will work until 12.04 and from then on refuse any later kernel
* install cd bootloader also has this check and refuses to even try to start the boot process

12.04 still has the non-pae kernels in the repositories (only some of the install CD-Images don't have it), so it is still possible to intall 12.04 without any nasty hacks but then upgrading to 12.10 will lead to problems with the kernel upgrades and apt-get getting stuck.

There is a recommendation to download 3rd party non-pae-builds of these new kernels and install them *manually* but it seems some of the Pentium-M are indeed capable of running the original Ubuntu pae kernel and only don't show this stupid flag in the cpuinfo. ThinkPad T40 definitely *can* run the pae kernels (and probably similar thinkpads too), its just the apt-get that will not allow these kernels to be installed.

[sudodus]

I have a T42 without pae. I'm running Lubuntu 12.04 now. Have you found any problem? I guess it would be a problem to run with more than 2 GB RAM (I have 1.25 GB).

Maybe I will get time to test your method during this week-end. (I can clone the internal drive to a USB drive to get a backup while I'm tampering with it).

[7bit]

I have a T42 without pae. I'm running Lubuntu 12.04 now. Have you found any problem? I guess it would be a problem to run with more than 2 GB RAM (I have 1.25 GB).

Maybe I will get time to test your method during this week-end. (I can clone the internal drive to a USB drive to get a backup while I'm tampering with it).

You can try to install

sudo apt-get install linux-generic-lts-quantal

this will pull in a bunch of other linux-* meta packages and linux-* packages from the 3.5 kernel (better save the list of packages it wants to install so you can remove them all again later) and then somewhere in the middle of this installation it will fail with error about missing pae and incompatible CPU and report broken/unconfigured packages (if it fails then remove everything it tried to install to make apt-get happy again)

if you run that script before you do this then apt-get will succeed and then you can reboot and it should boot with the new pae kernel although the CPU is not officially pae capable.

The script is only there to make apt-get believe it is ok to install these kernels, it does not affect the kernel itself, you need to run it only before you do a kernel update to suppress the pae related apt-get errors.

[7bit]

cat /proc/cpuinfo | grep sizes
address sizes : 36 bits physical, 32 bits virtual

It seems these Pentium-M do indeed have PAE built in and just do not announce it in their flags, otherwise there would be no way this CPU could have 36 bits physical address space (64GB) instead of 32 bit (non-pae, 4GB)

This means my method would work for all those Laptops that don't have pae in the flags but still have 36 bits physical address space.

The CD-Bootloader should be fixed to check for physical address space instead of that flag (which was accidentally forgotten in these particular Pentium-Ms) and the .deb install scripts should also be fixed to not grep for "pae" but for "36 bits physical" instead.

[sudodus]

You can try to install

sudo apt-get install linux-generic-lts-quantal

this will pull in a bunch of other linux-* meta packages and linux-* packages from the 3.5 kernel (better save the list of packages it wants to install so you can remove them all again later) and then somewhere in the middle of this installation it will fail with error about missing pae and incompatible CPU and report broken/unconfigured packages (if it fails then remove everything it tried to install to make apt-get happy again)

if you run that script before you do this then apt-get will succeed and then you can reboot and it should boot with the new pae kernel although the CPU is not officially pae capable.

The script is only there to make apt-get believe it is ok to install these kernels, it does not affect the kernel itself, you need to run it only before you do a kernel update to suppress the pae related apt-get errors.

After cloning the drive I started:

- Your script warned that there are only 32 bits physical and virtual memory.

- I continued with

sudo apt-get install linux-generic-lts-quantal

and it worked without complaints.

- I rebooted and the system is now running '3.5.0-23-generic'

sudodus@usb-lub:~$ uname -a
Linux usb-lub 3.5.0-23-generic #35~precise1-Ubuntu SMP Fri Jan 25 17:15:33 UTC 2013 i686 i686 i386 GNU/Linux
sudodus@usb-lub:~$ grep 32 /proc/cpuinfo 
address sizes	: 36 bits physical, 32 bits virtual
sudodus@usb-lub:~$ grep pae /proc/cpuinfo 
sudodus@usb-lub:~$ ls -l /boot
...
-rw-r--r-- 1 root root 20115951 feb  1 20:59 initrd.img-3.2.0-37-generic
-rw-r--r-- 1 root root 21716879 feb 10 18:33 initrd.img-3.5.0-23-generic
...

Can you confirm that this is a pae kernel, that is now running in my T42 with Pentium M processor without pae?

model name      : Intel(R) Pentium(R) M processor 1.70GHz

And now it recognizes 36 bits physical memory.

Done

[megrimm]

yes, I can boot to another kernel but then no matter what, when i try to install fake-pae, I still get:

megrimm@megrimm-lubuntu-t42:~$ sudo apt-get install fake-pae
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
linux-image-extra-3.5.0-25-generic : Depends: linux-image-3.5.0-25-generic but it is not going to be installed
linux-image-generic : Depends: linux-image-3.5.0-25-generic but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

... and 'apt-get -f install' meets me with:

This kernel does not support a non-PAE CPU.
dpkg: error processing /var/cache/apt/archives/linux-image-3.5.0-25-generic_3.5.0-25.39_i386.deb (--unpack):
subprocess new pre-installation script returned error exit status 1
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.5.0-25-generic /boot/vmlinuz-3.5.0-25-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.5.0-25-generic /boot/vmlinuz-3.5.0-25-generic
Errors were encountered while processing:
/var/cache/apt/archives/linux-image-3.5.0-25-generic_3.5.0-25.39_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)


so i feel stuck.

m

[sudodus]

I would try to remove the 'too new kernel packages'

sudo apt-get remove linux-image-3.5.0-25-generic

sudo apt-get remove linux-image-extra-3.5.0-25-generic

and then re-write the grub boot information with

sudo update-grub

[megrimm]

all i get from the first two commands is:

megrimm@megrimm-lubuntu-t42:~$ sudo apt-get remove linux-image-3.5.0-25-generic
[sudo] password for megrimm:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package 'linux-image-3.5.0-25-generic' is not installed, so not removed
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
linux-image-extra-3.5.0-25-generic : Depends: linux-image-3.5.0-25-generic but it is not going to be installed
linux-image-generic : Depends: linux-image-3.5.0-25-generic but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).
megrimm@megrimm-lubuntu-t42:~$ sudo apt-get remove linux-image-extra-3.5.0-25-generic
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
linux-image-generic : Depends: linux-image-3.5.0-25-generic but it is not going to be installed
Depends: linux-image-extra-3.5.0-25-generic but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).