# New kernel wont boot - how to find the reason

## m.s.w

Hi,

I was using 2.6.36 gentoo-sources. Decided to udpate to 2.6.38 (r-2, r5). The usuall method of update I use, and was always workin was to copy .config file from previous source tree to the new kernel source directory and then "make menuconfig", and the rest of required steps (update lilo.conf, copy bzImage etc.)

I use lilo as a boot manager.

It alway worked, bot not this time. This time it starts to load kernel and the screen goes black  - nothing happens, machine is locked. I think it is locked. After cold reboot i see no trace of the failed boot in syslog. It appears to me, that it stops just at the moment when it should load uvesafb drivers (framebuffer).

My question is how can I find out what is wrong? Because there is no log entry of the failed boot I can't be 100% sure at what point this boot process stops and I would like to find out. 

What would you do if it would happened to you?

I have the possibility to boot into previous kernel, so I have acces to my machine, I can always revert to previous kernel, but you know - what a hell, why can't I use latest available kerneL?

Things I know are the same in new kernel, and in previous kernel:

- root file system compiled in the kernel as it was before update

- drivers - of main components - the same

- no new hardware

Best Regards,

m.s.w

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## cach0rr0

recent X depends on KMS

KMS and framebuffer drivers do not work together - having both causes this exact issue 

You should enable KMS for your card within your kernel (labeled as "automatic modesetting" or some such, underneath the Direct Rendering Manager menu), and disable uvesafb

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## m.s.w

WOW!

That's a fast reply. Thanks for the tip - I will check it.

m.s.w

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## m.s.w

At first I didn't exactly knew what are you talking about, so I was excited that I have a quick and simple solution. But now I read some about KMS and it appears that I have to use non-KMS system because I have nVidia adapter and I use nvidia drivers. So unfortunately I still don't know how to resolve the problem.

Anyone has some ideas of how to find out what is the problem?

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## Bircoph

Try to use vga (text mode) console.

It works on my nvidia-gpu system with 2.6.37.4, haven't updated to 2.6.38 yet.

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## m.s.w

 *Bircoph wrote:*   

> Try to use vga (text mode) console.
> 
> It works on my nvidia-gpu system with 2.6.37.4, haven't updated to 2.6.38 yet.

 

Are you trying to tell me, that with the newest kernel it is impossible to use framebuffer?

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## v_andal

 *m.s.w wrote:*   

>  *Bircoph wrote:*   Try to use vga (text mode) console.
> 
> It works on my nvidia-gpu system with 2.6.37.4, haven't updated to 2.6.38 yet. 
> 
> Are you trying to tell me, that with the newest kernel it is impossible to use framebuffer?

 

No, it's just an attempt to isolate the problem  :Smile: 

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## billium

It may be the way you are summarising in the text above, but do you copy your old .config file to the new Kernel directory & 'make oldconfig' before 'make menuconfig'?

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## m.s.w

I am returning to this topic, because I have never resolved it. I just used plain text mode. But again, I would like to solve it. Can you help?

This time, with kernel gentoo-sources-3.3.0 i get 

```

Apr 6 01:26:57 mkm-box kernel: [     0.952630]  uvesafb: failed to execute /sbin/v86d

```

I did exactly what spock's site telling me to do

I have CONFIG_INITRAMFS_SOURCE="/usr/share/v86d/initramfs

I have CONFIG_FRAMEBUFFER_CONSOLE=y

I have CONFIG_FB_UVESA=y

Klibc was reemerged. V86d as well.

So what do I miss? At the moment i have black screen and the computer is frozen.

My graphic card i Nvidia GTX460

I can't see any logs in /var/log/messages concerning failed boot.

Would you be so kind and share some ideas of tracking this problem down?

Best Regards,

m.s.w

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## BillWho

m.s.w,

Strange problem indeed. I've traversed up the kernel versions without incident until recently. The only one I have a problem with now is linux-3.4-rc1.

Did you make oldconfig? For each updated kernel that's the first thing I do. If there were no functional additions, then it just drops out when completed. Otherwise you'll  be prompted to answer whether or not you want to include the new support or not. 

Did you compile the nvidia drivers for the new kernel? I have a script that builds the kernel, nvidia and vbox modules so I don't forget anything.

Did you try booting to runlevel 3? That might help with narrowing down the problem.

Just some thoughts for lack of any brilliant revelations    :Confused: 

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## Hu

In the original part of the thread, the OP indicated an intent to use the proprietary nVidia drivers.  OP, do you still use them?  If so, does the problem occur even if you remove the proprietary drivers?

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## m.s.w

Hi !

Thank you for your input.

To answer some of your questions: I always boot to runlevel 3 (I dont use any login managers). Screen goes black exactly after initialization of a kernel at the point of loading v86d. I don't have nvidia compiled in kernel. I use proprietary nVidia drivers. But removing them doesn't help much.

So, at the moment, I can't use framebuffer for some reason, I can't use KMS because i have nVidia, so I am left with simple text console with huge letters. This is baaaaad. To be honest  - i know i can start x and use any *-term (I use aterm) for work. But hey - each problem can be solved in Linux right? I am sure that here are many persons with the same graphic card and the same kernel and they have no problem with fb. Or am I so uniqe?

Best Regards,

m.s.w

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## Hu

As far as I know, you must use the framebuffer if you use KMS.  You must use the framebuffer to get a high resolution text mode.  I am unsure whether KMS is required to use the framebuffer.  I always enable KMS because of its other advantages.  KMS works well on my nVidia-based card.  I do not use the proprietary nVidia drivers.  I suggest you try removing them, enabling framebuffer KMS, and checking whether the result behaves as you expect.

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## m.s.w

Nope,

v86d can't be loaded. Framebuffer doesn't work at all. I'm stuck. Don't know what to check/change. I wonder if some error messages concerning locales during reemerging of klibc may have soemthing to do with it.

m.s.w

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## Gusar

You could try compiling v86d dynamically, that is not with klibc. Or you use vesafb instead of uvesafb.

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## toralf

And what's about using the "vga=..." grub kernel command line parameter ?

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## ultraslinky

m.s.w, have you tried the nouveau drivers? I tried them on my desktop with an Nvidia 9800GT and also the console was displaying in high resolution  :Smile: 

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## DirtyHairy

Also, you might try to go for the old-fashioned vesa kernel framebuffer driver instead of uvesafb which does not require anything from userland. The downside is that you may not get all resolutions that your monitor supports.

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## DaggyStyle

I don't know if it is related but gentoo kernel upgrade guide states that when taking a old .config and inserting it into a newer kernel, one must run "make oldconfig".

if you haven't done that, I'd suggest you'll start the upgrade again and this time run the command I mentioned.

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