Moving from 2.4 to 2.6 guide

sanity · n00b Joined: 19 May 2002 Posts: 39 Location: Iowa

I installed 2.6 when I realized it was finally in 2.6 testing stages, so I think I started with test2 or something. This is my story, hopefully it will be helpful to others.

First of all, the kernel itself. Look before you patch -- several things have been integrated, including (for example) touchpad support. make menuconfig still works. make xconfig seems to be the kde version, and make gconfig works fine if you've got gtk. Only thing about gconfig is, you press a "save" button at the top to save it, and you get no confirmation that it's actually saved. So save it a few times and hope it worked :roll:

My first few attempts failed because I had no output to my screen once the kernel had actually been booted. I believe this is related to a problem I had with serial IO being required in places it really doesn't seem like it should. Anyhow, there are a few things you should compile in that were previously assumed (only one I really care about is pcspkr):

Under "Code Maturity Level Options", enable everything. Lots of good stuff is, as usual, "experimental".

Under "General Setup", be sure to enable "Support for paging of anonymous memory". That's support for swap!

Under "Loadable Module Support", enable all but module versioning support, unless you know what you're doing more than I do.

Under "Device Drivers" -> "Input Support", read through everything. Be careful. It is now possible to disable the use of keyboards. Also, pay attention to things like "PS/2 keyboard/mouse controller" -- it can be a module, but think about it.

Under "Device Drivers" -> "Sound", you want ALSA drivers, and you want them all compiled in until they work otherwise. You should probably "emerge -C alsa-drivers" if you had them before, and note that the /etc/init.d/alsasound script breaks when the modules are compiled in. You'll have to hack it or write your own -- I still haven't solved it myself.

Under "File Systems" -> "Pseudo File Systems", pay attention. Enable /proc and /dev/pts. Devfs is officially obsolete, so you probably want to "emerge udev". (devfs is in userland now.) I have yet to do that, I'm still on the old kernel support. Maybe some scripts need to be updated? Knowing gentoo, you're probably on top of this

Those are the main surprises in the kernel itself. Now, for LVM and EVMS, note that both LVM and EVMS are no longer in the kernel. Instead, there's an option in the kernel under "Device Drivers" -> "Multi-Device Support" -> "Device Mapper". You want to emerge lvm2. I think evms2 is stable now, so just emerge evms. I don't use either on this box, but lvm2 works fine on two others.

Also, as noted elsewhere in this thread, you need to create /sys manually -- sysfs gets mounted there (assuming you enabled it in the kernel, which you really should). I'm not sure now which things belong in /proc, which in /sys, and which in /dev, but that's the way it is.

In general, any packages that provided kernel modules and have not been updated for 2.6 will be broken now. Not may. Will. For now, if you were using xfree86-drm, that's in the kernel now, near the AGP support. X itself should interface nicely, unless you updated your system headers (/usr/include/linux and such). I've found things to be much more often binary-compatible with 2.6 than source-compatible, so stay with the official 2.4.19 (or whatever they are now) headers.

About mice. Be aware that even if you have a PS/2 mouse, /dev/input/mousex (where x is the number of your mouse, from 0 on) and /dev/input/mice include support for PS/2 mice. /dev/psaux should still work, but I'd say it's depricated. So /dev/input/mice will have all your mice -- it has my PS/2 touchpad and my USB mouse. It also works for touchpad support if you compiled that in. Most importantly, more than one proccess can read from the /dev/input/* devices. I just followed a config for an IMPS/2 wheelmouse on /dev/input/mice, and forgot about gpm (since it can't handle touchpads).

Speaking of /dev/input (and the keyboard as a module), you really have no excuse left not to use USB support if you have it. Having hotplug installed and most of the modules I needed, I unplugged my Logitech mouse, removed the dongle that converts its USB to PS/2, and plugged it back in. My X didn't know the difference. In fact, I think my BIOS is even supporting USB keyboards now, and can boot off a USB2 mass storage device.

The only thing that is really broken for me now is my ATI support (which never really worked; I'm getting an nvidia soon), swsusp and intermezzo (which I also never got to work), and the alsa scripts, which is fine with me -- I can restore my own mixer levels.

As for performance, lots of things were noticably faster. For one thing, even with PORTAGE_NICENESS set at a default of 3, I can comfortably play music (even PSF files!) and browse while merging. Either it's a lot faster or better at multitasking, or it somehow knows which programs I'm interacting with and runs those faster. Whatever it is, purely on an intuitive level, it feels faster.

It's also been running for over a week on this laptop, twice (I had to shut it down once running out of battery, and another time I accidentally knocked the power cord while changing the battery. On my router, uptime is 16 days. I haven't noticed any actual crashing except when I was playing with swsusp and intermezzo. I think the only things that need work are compiling (some things don't compile/work as modules, and some things are apparently optional but are critical to the functioning of most other things) and compatibility, which is really not too bad. The only things you need to update/remerge are things that are really close to the kernel / kernel development -- modutils, for instance, is replaced with the package module-init-tools. Most of these will be taken care of for you, just watch out for lvm/evms and any packages that (attempt to) build modules.
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jamesw · n00b Joined: 16 Nov 2003 Posts: 5

When I installed Gentoo 1.4 with a 2.4 kernel, I accessed my CDROM through /dev/cdroms/cdrom. Now that I'm using 2.6.0-test9, that device file has disappeared, as has /dev/hda, which is the device I used under RHL to use the cdrom. The kernel does recognize the CDROM:

georwell · Posted: Thu Nov 20, 2003 2:50 pm Post subject: ALSA Problems

If your having ALSA problems. Make sure and recompile alsa-utils and alsa-libs. Then you might need to run ./snddevices that is in alsa-drivers. I wasn't able to get sound until I did this.

Now everything is working GREAT. I am so glad that the 3com 3c990-TX is working natively!! YEA!!!

jamesw · n00b Joined: 16 Nov 2003 Posts: 5

I fixed my CDRW problems with the following steps:

1. Removed SCSI emulation support from the kernel
2. Installed cdrtools-2.01_alpha19 with

xslf · n00b Joined: 22 Nov 2002 Posts: 6

gigatexal · Posted: Mon Nov 24, 2003 7:01 am Post subject: Re: my story / guide

gwion · Posted: Thu Nov 27, 2003 2:50 am Post subject:

i tried the 2.6-test10-mm1 kernel today and pretty much everything worked out of the box. i just have a maybe not so unimportant question:

when finally at the desktop and i try to su to root... i get: su: programme not found...

any suggestions? i searched the forum but i probably searched for the wrong thing...

help is appreciated

many thanks in advance!!!

cheers,

gwion
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cybrjackle · Apprentice Joined: 09 Jan 2003 Posts: 248 Location: USA

Is "lvm2" not avaible for gentoo-sources?

cybrjackle · Apprentice Joined: 09 Jan 2003 Posts: 248 Location: USA

I think I figured it out? :maybe:

Deepu Sudhakar · Tux's lil' helper Joined: 30 Aug 2003 Posts: 84

Sorry to bring up an old topic, but this might be useful.

ncec you get a 2.6 kernel working, make sure to recocmpile glibc. You will get NPTL support with it, and that will make threading so much better in your applications.

sj7trunks · Posted: Tue Dec 09, 2003 7:05 pm Post subject: lm_sensors and usb mouse/keyboard

After recently switching to kernel 2.6.0-test11... I was irritated by lm_sensors not working correctly. After researching the issue, they moved i2c from /proc to /sys. you can find it in /sys/bus/i2c/ and it does work, you just need to grab the latest lm_sensors CVS from http://secure.netroedge.com/~lm78/

As for those having problems with usb mouse/usb keyboard, the kernel has two different drivers along with 2 different hubs, ohci and ehci. you might want to go over your old config and see which worked for you. I'm currently using ohci bus and usbkbd and usbmouse drivers which works for me and doesn't do any of those weird effects others have listed in this topic.

ikaro · Advocate Joined: 14 Jul 2003 Posts: 2527 Location: Denmark

hi sj7trunks

you made it to the devs :> congrats
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manywele · l33t Joined: 12 Jul 2003 Posts: 739 Location: Inside

raab · n00b Joined: 02 Dec 2003 Posts: 19

I love it when this happens. You compile the kernel - everything works fine including sound (ALSA). You go to bed, jump on the PC (hasn't been rebooted) now sound doesn't work, there's no errors no nothing, its like the sounds muted even though Master and PCM are at 100.. fantastic, it's time's like this that makes me want to rm -rf / >_<
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aderio · Posted: Sun Dec 14, 2003 6:14 pm Post subject:

I'm just about to jump in at the deep end, and "risk" damaging all the hard work getting Gentoo 1.4 Kernel 2.4 by installing Kernel 2.6.

Anyone got any final words of wisdom before I start.

i.e.

Cflags for an Athon tbird 1300 (current "-march=athlon-tbird -o3 -pipe -fomit-frame-pointer")

Oops almost forgot I've 1.4 Gb RAM does this need a n enterprise kernel as I apparently need in an other distro for the system to recognise it.

Thanks in advance
Mr Happy
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stuorguk · Posted: Mon Dec 15, 2003 12:35 am Post subject:

My Promise Ultra100 HD controller won't work with 2.6. Fortunately I don't boot from that controller, so everything else functions. I have compiled in support. Any ideas?

ali3nx · Posted: Tue Dec 16, 2003 10:54 am Post subject:

i'm currently compiling 2.6.0-test11-bk11 with gcc-3.3.2-r4 and i will report my results as soon as possible. I'm posting here because i'm migrating from 2.4.23 and this is my first 2.6 kernel. I'm not using a portage version and this time this patchset is the very latest 2.6 kernel code available

Hope all goes well
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ali3nx · Posted: Wed Dec 17, 2003 12:04 pm Post subject:

Things couldn't have gone better considering the items i compiled support for... Allot of the time less is better. After reboot my network didn't start but a quick modprobe 8139too, ifconfig eth0 up, ifconfig (to check that my network was active) then echo 8139too >>/etc/modules.autoload.d/kernel-2.6 and a reboot later everything was mostly operational. :lol:

Not too many problems to report sofar... no mysterious segfaults or oddities conidering i'm running a one day old kernel snapshot. xserver did work right away but sofar framebuffer resolutions have been poor... More testing is needed with regards to this issue. It may be my own configuration and unfamiliarity with the 2.6 kernel. All my Ipv6 network tunnels also worked after reconfiguring them... I'm still researching how to make sit tunnels restore to thier previous state after reboot. Hotplug or module init tools did get a bit hyperactive with loading sound modules that i don't have devices for but it didn't cause any problems with system stability. I wanted to compile lots of stuff to make something break but that didn't really happen with the exception of my network driver not loading after the first reboot. One very encouraging note... Memory usage on my server dropped 120MB just by chaging to this kernel branch... Linus whatever you and your maintainers are doin to this code... keep it up it's working great :wink:

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DumbAss · Posted: Wed Dec 17, 2003 2:01 pm Post subject:

bruor · Apprentice Joined: 08 Jul 2003 Posts: 239

ive noticed a few people are talking about usb support, just thought i would post this in case it helps someone, ehci is for the usb 2.0 controller hub while ohci (nforce2 boards) is for the usb 1.1 hubs. while the motherboard may have both types onboard teh manual will tell you which port actually support the usb 2.0, this happens becasue they connect both hubs to teh same physical port and the port then autosenses the device. also most of the time the manufacturers will only connect the 2.0 root hub to 2 ports on the back..

hope this help

gamezfreak · n00b Joined: 15 Dec 2003 Posts: 26

I am new to gentoo and am a novice,but not n00b, at kernel compiling. I followed the procedure given at the beggining of this post to emerge the kernel and then make the bzImage. All of that went well without any errors, but when I try to load the new kernel I get an error:

VFS: Cannot open root device "hdb2" or hdb2
Please append a correct "root=" boot option
Kernel Panic: VFS: Unable to mount root fs on hdb2

I set up my grub.conf file based upon my previous setting, which still works.

My /boot/grub/grub.conf file contains:
-----
default 0
timeout 0
splashimage=(hd1,0)/grub/splash.xpm.gz

title=Gentoo Linux-2.6.0
root (hd1,0)
kernel (hd1,0)/vmlinuz-.6.0-test11 root=/dev/hdb2

title=Gentoo Linux-2.4.20-gentoo-r9
root (hd1,0)
kernel (hd1,0)/kernel-2.4.20-gentoo-r9 root=/dev/hdb2
initrd (hd1,0)/initrd-2.4.20-gentoo-r9

title=Windows XP Pro
root(hd0,0)
chainloader +1
-----

My /boot directory contains:
-----
System.map
System.map-2.4.20-gentoo-r9
System.map-2.6.0-test11
bzImage
config-2.6.0-test11
/grub
initrd-2.4.20-gentoo-r9
kernel-2.4.20-gentoo-r9
/lost+found
vmlinuz-2.6.0-test11
-----

I would appreciate any suggestions as to how to fix this.

ali3nx · Posted: Thu Dec 18, 2003 2:40 am Post subject:

gamezfreak root=/path/to/your/root/partition should be what is listed in your kernel config line... here's my grub.conf to help you...

#
# h3x4g0n boot menu configuration file
#

# Boot automatically after 10 secs.
timeout 10

# By default, boot the first entry.
default 0

splashimage=(hd0,0)/boot/grub/splash.xpm.gz

# Fallback to the second entry.
fallback 1

title=linux-2.6.0-test11-bk12
root(hd0,0)
kernel (hd0,0)/boot/vmlinuz root=/dev/hda3 hdc=ide-scsi vga=792

title=linux-2.6.0-test11-bk11
root(hd0,0)
kernel (hd0,0)/boot/vmlinuz.old root=/dev/hda3 hdc=ide-scsi

#framebuffer was not compiled into -bk11 :oops:

title=2.4.23-vanilla
root(hd0,0)
kernel (hd0,0)/boot/vmlinuz-2.4.x3 root=/dev/hda3 hdc=ide-scsi vga=792

# For installing GRUB into the hard disk
title Install GRUB into the hard disk
root (hd0,0)
setup (hd0)

# Change the colors.
title Change the colors
color light-green/brown blink-red/blue

and my "system" filesystem...

Filesystem Size Used Avail Use% Mounted on
/dev/hda1 99M 11M 83M 12% /boot
/dev/hda3 9.2G 226M 8.5G 3% /
/dev/hda5 14G 7.5G 5.7G 57% /usr

/dev/hda6 14G 7.4G 5.7G 57% /var
/dev/hda7 4.6G 38M 4.4G 1% /tmp
/dev/hda8 4.6G 562M 3.9G 13% /opt
/dev/hda9 1.9G 312M 1.5G 18% /root
/dev/hda10 5.6G 3.1G 2.3G 58% /home

As you can see root=/dev/hda3 is where my rootfs is located. The reasoning for needing this variable is due to the kernel needing to find a binary named "init" that is located in /sbin and I've personally found out what happens when sbin is moved off of the rootfs onto it's own separate partition :oops:

Your kernel just panics because init is the first program that the kernel starts thats required to start the rest of the system. It looks like thats possibly the error your having.
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maomao0407 · n00b Joined: 05 Dec 2003 Posts: 65

good article

ali3nx · Posted: Thu Dec 18, 2003 4:55 am Post subject:

maomao0407 danke

allways rewarding to help someone
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chomber · n00b Joined: 18 Aug 2003 Posts: 35

I 'm not sure if this is already answered somewhere but...

Is it possible to use old config from 2.4 as a base config for kernel 2.6?
So is 'make oldconfig' working still this kind of migration?