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Author Topic: PAE issue with VL 7.1 light  (Read 433 times)

Assaf-h

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PAE issue with VL 7.1 light
« on: April 01, 2016, 04:22:19 pm »

Hi.
I have a PAE issue with V.L 7.1 Light

when starting VL 7.1 light on IBM R50e the installer need me to write "gui forcepae" in order to start.

After the installation grub has two option:
1. Vector Linux 7.1 light GUN/Linux, linux 3.18.18-this option does not boot and give an massage: "unable to boot - please use kernel appropriate for your CPU
2. Vector Linux 7.1 light GUN/Linux, linux 3.18.18(TUI) -this option boot into console and it is possible to login and startX at the end.

How do I fix the first option to boot into GDM on this IBM R50e...?

thanks

Assaf

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roarde

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Re: PAE issue with VL 7.1 light
« Reply #1 on: April 02, 2016, 09:50:32 pm »

First, be aware that "forcepae" is not officially supported.

If you want to keep trying, it would be interesting to see why it does boot when starting TUI.

Please post the output of the following two lines. You need to be root.
Code: [Select]
grep linux16 /boot/grub/grub.cfg
grep -A11 '(TUI)' /boot/grub/grub.cfg | grep linux
Note: That last one is "grep -A(number eleven)", in case it's hard to tell "l" from "1" in the font you're using. We want the eleven lines following "(TUI)" to be searched for "linux".

That will show the kernel command lines for graphical and text startup. We're looking to see where the "forcepae" from the installer was put, if anywhere at all.
« Last Edit: April 02, 2016, 10:26:24 pm by roarde »
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Robert
VL 7.1 Light

Assaf-h

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Re: PAE issue with VL 7.1 light
« Reply #2 on: April 08, 2016, 01:15:40 pm »

Hi 
sorry for my  late response.

I have the following output :
Code: [Select]
root:# grep linux16 /boot/grub/grub.cfg
        linux16 /boot/vmlinuz-3.18.16 root=/dev/sda1 ro quiet splash vga=788

root:# grep -A11 '(TUI)' boot/grub/grub.cfg | grep linux
        linux   /boot/vmlinuz-3.18.16 root=/dev/sda1 ro 2


any idea what next?

Assaf
« Last Edit: April 08, 2016, 01:25:50 pm by Assaf-h »
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M0E-lnx

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Re: PAE issue with VL 7.1 light
« Reply #3 on: April 08, 2016, 01:32:46 pm »

FYI,
I have started a project on our git host to build an un-official non-pae enabled kernel, just in case you guys want to experiment with it.  I know i've heard about this before, people wanting to use a non-pae kernel.

The project will be hosted here  http://vlcore.vectorlinux.com:10080/git/m0e.lnx/kernel3.18-nonpae
There are currently no files there yet, I'm working on migrating the current setup from 7.1 into there and make the necessary modifications.

Files and test packages coming soon.

roarde

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Re: PAE issue with VL 7.1 light
« Reply #4 on: April 09, 2016, 11:50:02 am »

@M0E-lnx: Thanks! I don't have the equipment to test this properly when that time comes, but I do have a more-than-usual interest in it.

@Assaf-h:
We'll try to keep your TUI boot working while testing just how to do this with the GUI boot, but from here on, you should be prepared to boot from a different medium (install disc should work) and mount the installation in order to make changes allowing you to boot at all.

As root, copy the present /boot/grub/grub.cfg to a safe backup location. Then edit the linux16 line in the existing /boot/grub/grub.cfg:
Code: [Select]
linux16 /boot/vmlinuz-3.18.16 root=/dev/sda1 ro quiet splash vga=788 forcepae
This may work. Even if it does, there are other changes that need to be made in order to keep it maintainable, so please post back with your results. It's also possible that there's something in the initrd that won't allow it, though I have no firm reason to suspect that. If there is, that can be worked around too, but it's much more detailed.

Just making the above edit and rebooting skips at least a few in-between test steps, but it's worth a try since there's nothing useful to be learned by doing the whole process if this does work.

If this does not work, please let us know whether having a graphical boot splash screen is important, or is it OK to have boot text scrolling by, then the regular graphical login you're used to?
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Robert
VL 7.1 Light

Assaf-h

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Re: PAE issue with VL 7.1 light
« Reply #5 on: April 11, 2016, 10:51:38 am »

@roarde:
Thank you - that was a grate tip. GDM now works. adding "forcepae" at the end of this line solved the problem

you wrote:
Quote
This may work. Even if it does, there are other changes that need to be made in order to keep it maintainable

well - it works...
What are the other changes that need to be done ?

assaf
 
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M0E-lnx

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Re: PAE issue with VL 7.1 light
« Reply #6 on: April 11, 2016, 01:37:29 pm »

roarde

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Re: PAE issue with VL 7.1 light
« Reply #7 on: April 11, 2016, 09:55:59 pm »

Assaf-h: I should have said "change", because there's only one edit to do. As root, edit the file /etc/default/grub. Add the line below somewhere before the line "### DO NOT EDIT BELOW THIS LINE ###":
Code: [Select]
GRUB_CMDLINE_LINUX="forcepae"
That will cause every linux kernel command line created by "grub-mkconfig" to have "forcepae" tagged on to its end, automatically. This will keep you from having to manually edit grub.cfg each time grub needs to be reconfigured. The only drawback is that I don't know what happens if you try to load a non-pae kernel this way. If you try one, it might be best just to remove th e forcepae part from grub.cfg by hand for that kernel.

Once you are finished with /etc/default/grub, as root run:
Code: [Select]
grub-mkconfig -o /boot/grub/grub.cfgThat will write the grub.cfg you actually want, which includes tagging "forcepae" onto the TUI kernel command line, too. After that's done, you can reboot or just wait to test it at your next regular startup.

Edit: The grub-mkconfig line in the code block above was originally incorrect, and has been fixed. Running the previous incorrect line would have been harmless, but of course it wouldn't have worked.

On the web, you will see references to "update-grub". That's a script or so that some distros use, which calls both "grub-install" and "grub-mkconfig". It might do a couple of other things. VL isn't offering one for now. IMO, it's not a good idea to create one and get users used to doing it a certain way until grub and its documentation settle down a bit.

If anyone is interested, [ . . .]
I actually was trying to count the number of times I've been asked whether a non-pae kernel is available. Gave up the counting part. There are some things I want to try with this myself, but they're very time-consuming so it'll be a while yet. But no doubt there will be those trying it soon. Just hope they give needed feeback.

Again, Thank You!
« Last Edit: April 13, 2016, 12:43:57 am by roarde »
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Robert
VL 7.1 Light

roarde

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Re: PAE issue with VL 7.1 light
« Reply #8 on: April 13, 2016, 12:45:25 am »

In the above post, the "grub-mkconfig" line was originally incorrect, but is now fixed. This post is to force a refresh for anyone interested who might have missed it otherwise.
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Robert
VL 7.1 Light

nightflier

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Re: PAE issue with VL 7.1 light
« Reply #9 on: April 16, 2016, 07:16:05 am »

If anyone is interested, the test packages are available here.

http://vlcore.vectorlinux.com/git/m0e.lnx/kernel3.18-nonpae/builds/185/artifacts/browse/kernel3.18-nonpae/

I tested those packages and it runs fine in a vm. However, the kernel still seems to be pae..  /proc/cpuinfo shows pae in "flags".

Tried booting it on a very old VIA C3, got message:
Code: [Select]
This kernel requires the following features not present on the CPU:
pae cx8 cmow
Unable to boot. Please use a kernel appropriate for your CPU
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M0E-lnx

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Re: PAE issue with VL 7.1 light
« Reply #10 on: April 17, 2016, 05:20:32 pm »

I think /proc/cpuinfo will show all the cpu capabilities, not necesarily what the kwrnel supports.  Ie, a 32bit os running on a 64bit cpu will still show the 64bit capabilities on cpuinfo although i wouldnt run 64bit code. I may be wrong though. 

nightflier

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Re: PAE issue with VL 7.1 light
« Reply #11 on: April 17, 2016, 05:44:15 pm »

I think /proc/cpuinfo will show all the cpu capabilities

That makes sense, didn't think about that. Guess the messages from the failed boot are more meaningful.
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