Oh, for cripes sake!!!

dpshak · Posted: Tue Nov 21, 2017 7:08 pm Post subject: Oh, for cripes sake!!!

I'm not sure where this goes...
But, seeing as it started on a kernel update, I'll put it here.

I run ~amd64 on this box, and I run the proprietary nVidia drivers - due to that bug in the Nouveau drivers that causes X to freeze.
Since, long about kernel-4.9.? - I can't remember WHERE it started but, whenever I do an 'emerge -uDav,' upgrade the kernel and reboot, it lands on the CLI login, instead of jumping to sddm.
That's normal, of course, because the nVidia drivers need to be rebuilt to work with the latest kernel.

The PROBLEM is: when it lands on the CLI login, the screen is flashing/flickering! On the hand-off from grub into the init stage, everything is normal. When it completes the init stage and lands at the CLI log-in, the screen starts flickering/flashing. When I try to log in, I can't, because it won't accept it - due to the flashing/flickering.
Currently, I'm running the 4.14.1 kernel. I had to boot in to the previous kernel - 4.13.12 - and into KDE and use Konsole to rebuild the nVidia drivers against the 4.14.1 kernel, and reboot the machine. Then it booted (because the nVidia drivers were rebuilt) into sddm and into KDE.
Interesting enough, now that I'm in KDE, if I do <CTRL-ALT-F1> it dumps me into a normal CLI prompt...no flashing/flickering.

Can somebody point me in the right direction to fix this?!?

John R. Graham · Posted: Tue Nov 21, 2017 7:23 pm Post subject:

Sure. Here you go:

If you have sshd running on this machine, then
1. Ssh into the machine and stop the xdm service.
Otherwise,
1. Boot the install media of your choice, chroot into your Gentoo installation as per the Handbook, and remove xdm from the default run level.
2. Exit the chroot and reboot (or just reboot if you're doing the ssh thing) into your normal Gentoo.
Run
Code:

emerge -1v @x11-module-rebuild
to get your kernel and x11 drivers in agreement.
Try starting xdm at the command line to make sure your installation is now sane again.
Once you know it is, then re-add xdm to the default runlevel.
Remember to rebuild your x11 drivers (as in #2 above) in the future whenever you update the kernel.

- John
_________________
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Jaglover · Posted: Tue Nov 21, 2017 7:33 pm Post subject:

That would be

NeddySeagoon · Posted: Tue Nov 21, 2017 7:42 pm Post subject:

dpshak,

To put some meat on the bone offered by Jaglover, emerge @module-rebuild rebuilds all of your out of tree kernel modules against the kernel pointed to by the /usr/src/linux symlink.
That need not be the running kernel.

It is left as an exercise for the reader to do things in the right order so that the nvidia driver 'justworks' at reboot into the new kernel.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

John R. Graham · Posted: Tue Nov 21, 2017 8:09 pm Post subject:

Neddy,

I know the OP's specific issue was with the nVidia driver, but wouldn't it be best practice to rebuild all the drivers? If so, there's a better set defined.

- John
_________________
I can confirm that I have received between 0 and 499 National Security Letters.

Jaglover · Posted: Tue Nov 21, 2017 8:15 pm Post subject:

John,

@x11-module-rebuild does not contain kernel modules.
_________________
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Please learn how to denote units correctly!

John R. Graham · Posted: Tue Nov 21, 2017 8:33 pm Post subject:

Hi Jaglover,

It does contain kernel modules that X uses. Or, more correctly, to my knowledge, it's always included nvidia-drivers. Check it out yourself.

- John
_________________
I can confirm that I have received between 0 and 499 National Security Letters.

Jaglover · Posted: Tue Nov 21, 2017 8:41 pm Post subject:

I do not have proprietary drivers in any box right now, so I have to take your word. It was my understanding @x11-module-rebuild rebuilds only X modules, I may be wrong.
_________________
My Gentoo installation notes.
Please learn how to denote units correctly!

dpshak · Posted: Thu Nov 23, 2017 11:15 am Post subject:

Thanks for the replies folks!

It's been my habit to 'emerge @module-rebuild' after I build a new kernel. When I'd reboot the machine, it would conveniently land at the CLI log-in, I'd log in and 'emerge @module-rebuild' where nVidia and virtualbox modules would be rebuilt. At least that's the way it always USED to work...

I just recently started using the nVidia drivers again, after having trouble with the nouveau driver, so maybe things have changed.

It would appear that the problem IS with the mis-matched nVidia driver module. Now that the module has been rebuilt against the new kernel, I can remove xdm from the default run level and the machine will boot to a stable command prompt.

I guess next time, I'll have to try 'emerge @module-rebuild' AFTER building the new kernel but BEFORE rebooting the machine. As NeddySeagoon says, that should work because the symlink is pointed at the new kernel. I'm a creature of habit: I've been doing it the other way forever and it 'just worked!'

krinn · Watchman Joined: 02 May 2003 Posts: 7470

or just ctrl+f2(f3...) ; screen1 flicker while xdm try to load/fail/load... but only screen 1 (7 also maybe).

NeddySeagoon · Posted: Thu Nov 23, 2017 12:22 pm Post subject:

dpshak,

I used to rebuild the nVidia-drivers against the kernel after starting the new kernel too.
It was never a problem for me as I never used a login manager.
There was never any point in waiting for X to fail to start before picking up the pieces :)

Things appear to be better now, maybe I'll use a login manager on my next system.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.