MiniMyth with kernel 2.6

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oeris
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Joined: Sat Oct 04, 2003 9:13 pm

MiniMyth with kernel 2.6

Post by oeris »

Hey everyone,

Last weekend I tried updating minimyth to use kernel 2.6 with all the epia kernel patches and XFree-epia6. I did this only cause I wanted to see how it worked out and for the "why not" factor.

I had all the kernel /XFree issues worked out on my normal desktop epia so there was nothing complicated in that front. Making the rootfs proved to be pretty hard as I upgraded pretty much every file in the system with new ones from my fedora core box. (mythtv cvs)

X took forever to configure until I figured out I could disable XkbDisable. For some reason 4.3.99 would not work without all the additional xkb stuff.

My final rootfs is about 23 megs, but I can probably tweek that further, unfortunately I couldn't get the rootfs made through cramfs. Even though its enabled in the kernel, the kernel just wouldn't see it as a valid ram image. So I had to make a loopback ext2 fs.

My question really if anyone knows is if there are issues with 2.6 and cramfs, or any new kernel options that I need to pass (I already read Documentation/ramdisk in the kernel source and followed all their advice. The reason I'm not liking it as an ext2 fs is cause it takes forever for the kernel to realize that its ext2 so I lose like 5-6 seconds on bootup.

Anyone have any recommendations? If someone wants the kernel (it.s 2.6.1 with all the epia patches) and the rootfs, I can send it. I can't host it at the moment unfortunately.

Oguzhan
lmatter
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Location: California, USA

Post by lmatter »

Oeris,

Thanks for the good info. I'm not quite ready to try 2.6 yet myself, but when I am I will be coming to you for help.

Larry
sglow
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Post by sglow »

I've been playing around with cramfs and a 2.6 kernel and had no problems. Note that I'm not doing much (not running myth at the moment) just experimenting.

I'm using 2.6.3 vanilla sources. I didn't put any of the epia patches in.

My root file system is made with cramfs and is a very minimal busybox system.

The hardware is an epia M10000

Here's the section from my pxelinux.cfg file that boots my 2.6.3 kernel:

Code: Select all

label test
KERNEL test/bzImage
APPEND initrd=test/root.cramfs ramdisk=64000
Steve
hagan
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Post by hagan »

Hi,
thats interesting. I was also playing around with 2.6 and did not get it working with cramFS. I used 2.6.2. Maybe that is the reason. Did you also try it with 2.6.2? What config options did you use? I am interested in 2.6 because of the suspend to RAM feature which seems not to be availible with 2.4.

Regards
Marcus
hagan
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Post by hagan »

Ok,
I just look at the 2.6.3 changelog and found following entry:

<James.Bottomley@SteelEye.com>
[PATCH] use cramfs as an initrd

Now that Al Viro fixed cramfs, it works beautifully as an initrd
filesystem.

So finally plumb it in.


That explains maybe a lot. I am looking forward to trying this out tonight.

Regards
Marcus
hagan
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Post by hagan »

Hi,
I get further with the 2.6.3 kernel, but still not to the goal. The kernel now initializes the RAMDRIVE and also loads the cramfs image but then nothing.
The last message I get is:

VFS: Mounted root (cramfs filesystem).

which looks good but then nothing more happens. The box is frozen. No error message. Nothing. I do not think the problem lies in the cramfs image, but in the kernel configuration. sglow: maybe you can send me your .config file. That would be great, just to make sure I configured the kernel correctly.

Thanks
Marcus
lmatter
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Joined: Sat Aug 23, 2003 5:13 pm
Location: California, USA

Post by lmatter »

I got this once in a while when I was building minimyth (using the 2.4 kernel). I'm trying to remember why. Here are some things to look at (I have not looked at 2.6 so some of this may not apply)

Make sure you enable initial ramdisk support. Also Compressed ROM (not RAM) was needed for cramfs, but it looks like you have that working

Make sure devfs is automounted (or pass devfs=mount command line).

make sure busybox is configured to be run as an initrd (it should have generated a /linuxrc symlink when you installed it). If you are just using my image you are ok.

Good luck.
Larry
sglow
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Post by sglow »

Hi Marcus;

I think I successfully sent you the .config file using the private message function. If you don't get it, or if it's difficult for you to use like that, just e-mail me.

sag@ollies.net

I get so much spam that I've given up on hiding my e-mail address!

Steve
hagan wrote:Hi,
I get further with the 2.6.3 kernel, but still not to the goal. The kernel now initializes the RAMDRIVE and also loads the cramfs image but then nothing.
The last message I get is:

VFS: Mounted root (cramfs filesystem).

which looks good but then nothing more happens. The box is frozen. No error message. Nothing. I do not think the problem lies in the cramfs image, but in the kernel configuration. sglow: maybe you can send me your .config file. That would be great, just to make sure I configured the kernel correctly.

Thanks
Marcus
hagan
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Post by hagan »

Hi sglow,
thanks alot. I got your kernel config. I will try it as soon as i get home.


Regards
Marcus
hagan
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Post by hagan »

Hi all,
I played around with this a while and got it not working. The error message I get on the most advaced attemts is:

RAMDISK: cramfs filesystem found at block 0
RAMDISK: Loading 32784 blocks [1 disk] into ram disk... done.
Kernel panic: VFS: Unable to mount root fs on unknown-block(3,1)

Did anybody see this before and maybe know a solution.

I tried various root images, beside the 0.4beta4. I tried the kernel configuration of sglow and various variations. In the moment I am a little bit lost.

Regards
Marcus
sglow
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Location: Sterling, MA, USA

Post by sglow »

Hi Marcus;

Yes, that message seems very familiar. I'm sorry to say I can't remember exactly what the problem was, but I think it was something pretty simple. Check the file permissions on the file system image to make sure that it's world readable.

Steve
MartinE75
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Location: AUSTRIA

Post by MartinE75 »

Hi,

anybody passed the kernel panic?

I gave it a try with vanilla-soruces 2.6.5 but also had to stop with the kernel panic.

wbr
Martin
MartinE75
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Post by MartinE75 »

Hi,

i have to report a "little" success.

I changed the system to boot with an NFS mounted root. This already works but i have troubles because the root filesystem is mounted read-only at the moment.

I am sure i can solve this issue and then it should work.

I also tested suspend-to-ram and it works. When i power up the device again, it seems to have problems with network configuration but this may also be due to the read-only rootfs.

I will continue to solve the problem this way...

Martin
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