kernel 2.6 migration steps?

[yardbird]

Hi there,

I read across the forums many stories of users trying the new 2.5 - 2.6 kernels. I think that it would be nice to gather in one thread all the steps needed to perform the 2.4->2.6 upgrade. That's what comes to my mind:

• 1. a new version of modutils is needed: the name is module-init-tools

  Code: Select all

  	emerge module-init-tools
  	

  This version of modutils is backward compatible with the 2.4 series;
  
  2. a new dir, /sys, is needed to mount the new sysfs filesystem. Gentoo init scripts take care to mount /sys at boot time (same happens with /dev/pts filesystem, which must be enabled in the kernel);
  
  3. regular users should now be also in the "tty" group (I noticed that if you don't konsole and xterm complain about not being able to chown /dev/pts/* - this could depend also upon devfs settings).

I also have a question about the new kernel: how should one change the kernel headers? I understood that they are needed during glibc compilation, and that they should not change after compiling glibc. Now I'm using the 2.4.19 header on a 2.6.0-test1 kernel. The question is: will it be needed, at a certain point, to recompile the whole system? Or just glibc? Are there going to be problems compiling software under 2.6 with 2.4 headers? Shouldn't the whole thing be retrocompatible?

So far for me kernel 2.6 works fine, with few minor glitches:

• 1. ati-drivers and pcmcia-cs and some other stuff won't compile (i guess they have to be ported...);
  2. ps2 mouse and touchpad issues: on my laptop with a vanilla 2.6.0-test1 I get a kernel panic(!) if I load the psmouse module while an external ps2 mouse is also connected. With -ac1 no kernel panic, but touchpad and mouse still won't work. I have to load psmouse with an extra option:

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  modprobe psmouse psmouse_noext=1
  

  to avoid all these problems, but advanced features (such as mouse wheel) are disabled. These issues are known, I hope they'll be fixed soon, IMHO it's a showstopper.

These are so far my experiences with 2.6. If I remember something else I'll post here. I hope this will help someone Happy testing!

[static]

1. True, you need to emerge module-init-tools
2. I get some message about something *not needed for sys in 2.6, but it whips by real quick <shrug>
3. Didn't have to add anyone to tty group - xterm doesn't complain for me
4. Had to add Unix98 PTY support into the kernel config, followed by /dev/pts in Pseudo Filesystems (/dev/pts only shows up once you've enabled Unix98 PTY under (*what was it?)

My Radeon works with the kernel DRM; don't need no ati-drivers or xfree-drm here. Your milage may vary.

I don't have a laptop, so no comment on the ps/2 mouse thing. My mouse works the same as it always did.

Newbies - Trying out the new kernel is pretty easy - You pretty much need about a half-hour to dedicate to configuring and compiling before you're ready to rock.

Kudos - yardbird; good idea for the thread. Will be helpful for doubtfuls

[iwasbiggs]

You can also unmerge alsa-driver once you upgrade.

[Lovechild]

What is this doing in Desktop Environments ??

[yardbird]

I get some message about something *not needed for sys in 2.6, but it whips by real quick <shrug>

I think that it says that it can't find the /sys dir which IS needed for 2.5-2.6 kernels... I misunderstood too the first time I read it

Didn't have to add anyone to tty group - xterm doesn't complain for me

Mmmhh... I had for sure konsole complaining. It runs fine anyway, it just says in background that konsole_grantpty could not set the ownership of the pty.

My Radeon works with the kernel DRM; don't need no ati-drivers or xfree-drm here. Your milage may vary.

I have a 9700, so I'm bound to ati-drivers for 3D acceleration

[pilla]

Hardly DE-related.

Moving to OTG.

[Lord Tocharian]

The first time I rebooted with the new kernel it complained about not being able to setup sysfs. I fixed this by manually creating the /sys dir. After a reboot, that cleared up the problem for me.

[weijia]

I too am interested in knowing how to get pcmcia-cs setup with the new kernel. Also, how is USB and PCI hotplugging handled now? With the same hotplug package? Thanks

[yardbird]

Hi,

I too am interested in knowing how to get pcmcia-cs setup with the new kernel. Also, how is USB and PCI hotplugging handled now? With the same hotplug package? Thanks

Don't know about hotplug, haven't tried yet. However it seems to be based upon bash scripts, my guess is that at most you have to tweak some configuration files.

About pcmcia-cs: I tried to compile it with both 2.4 and 2.6 headers, but there was a compilation error on "scsi.h". It seems to involve the user space app (i.e. cardmgr demon, not the drivers themselves), so I just kept the cardmgr compiled under 2.4 and then, under 2.6, I used the drivers shipping with the kernel. It's an ugly thing, but it seems to me the only way until pcmcia-cs compiles under 2.6

[weijia]

I have a version of pcmcia-cs compiled from the 2.4 kernels. When I try to use them under 2.6, it complains that the 'ds' module is not available. However, I do not know where to enable this under kernel configs to get this. Any ideas? Thanks

[yardbird]

I have a version of pcmcia-cs compiled from the 2.4 kernels. When I try to use them under 2.6, it complains that the 'ds' module is not available. However, I do not know where to enable this under kernel configs to get this. Any ideas? Thanks

I don't think there is any module named "ds" in the PCMCIA drivers in the kernel. You simply should modprobe the modules for your PCMCIA socket (mine is yenta_socket, another one is i82365... others are listed in the PCMCIA kernel submenu. I suggest you to compile all the drivers available as module, so that you can try all the possibilities). Then start the cardmgr demon.

[sa]

I just got pcmcia working for 2.6.0-test1.

first I had to enable all the pcmcia stuff in the kernel then

I just had to edit /usr/src/linux/include/scsi/scsi.h
and make lines 228-30 look like:

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typedef struct scsi_lun {
    u_int8_t  scsi_lun[8];
} ScsiLun;

then emerge pcmcia-cs
then I just had to add "yenta_socket" to /etc/modules.autoload.d/kernel-2.6

It up and running now with my linksys wpc11 card.

hth,
sa

[yardbird]

I just got pcmcia working for 2.6.0-test1.

first I had to enable all the pcmcia stuff in the kernel then

I just had to edit /usr/src/linux/include/scsi/scsi.h
and make lines 228-30 look like:

Code: Select all

typedef struct scsi_lun {
    u_int8_t  scsi_lun[8];
} ScsiLun;

then emerge pcmcia-cs
then I just had to add "yenta_socket" to /etc/modules.autoload.d/kernel-2.6

It up and running now with my linksys wpc11 card.

hth,
sa

Thanks for the tip, I'll try as soon as possible..

[Halanegri]

I also have a question about the new kernel: how should one change the kernel headers? I understood that they are needed during glibc compilation, and that they should not change after compiling glibc. Now I'm using the 2.4.19 header on a 2.6.0-test1 kernel. The question is: will it be needed, at a certain point, to recompile the whole system? Or just glibc? Are there going to be problems compiling software under 2.6 with 2.4 headers? Shouldn't the whole thing be retrocompatible?

Any word on this? I have looked at the glibc-2.3.2-r1 ebuild, and it looks for the 2.5/2.6 kernel in order to check whether it should enable nptl and such, so will recompiling glibc be neccessary?

[yardbird]

I also have a question about the new kernel: how should one change the kernel headers? I understood that they are needed during glibc compilation, and that they should not change after compiling glibc. Now I'm using the 2.4.19 header on a 2.6.0-test1 kernel. The question is: will it be needed, at a certain point, to recompile the whole system? Or just glibc? Are there going to be problems compiling software under 2.6 with 2.4 headers? Shouldn't the whole thing be retrocompatible?

Any word on this? I have looked at the glibc-2.3.2-r1 ebuild, and it looks for the 2.5/2.6 kernel in order to check whether it should enable nptl and such, so will recompiling glibc be neccessary?

Well, I can tell you what I've understood. Someone corrects me if I'm wrong.

Recompiling glibc should NOT be necessary, as long as you keep the kernel-headers with which you compiled glibc in /usr/include/linux and as long as you don't need the new features available in 2.5-2.6. However if you need these features you should:

1. substitute the 2.4 headers with those from 2.6;
2. recompile glibc;
3. emerge -e world, so that all the packages you installed are recompiled.

I really don't know if it is a smart move to do this now, since there still may be some changes in the kernel that would request you to recompile everythiong once again later (can anyone confimr this?). Hope this helps, I'm still learning about this though...

[Halanegri]

1. substitute the 2.4 headers with those from 2.6

When you are bootstraping, you don't have ANY kernel headers in /usr/src, so how can glibc benefit from the headers?(and why is it ok to have no headers there during bootstrap if you NEED them to use the 2.4 kernel?)

[yardbird]

When you are bootstraping, you don't have ANY kernel headers in /usr/src, so how can glibc benefit from the headers?(and why is it ok to have no headers there during bootstrap if you NEED them to use the 2.4 kernel?)

MMhhh.. Don't know about this, I should check out, you've got a point here. I read somewhere that some time ago there was a discussion (maybe on lkml?) about the opportunity to ship, together with glibc, a "safe" set of kernel-headers. Maybe those headers are used when compiling glibc during bootstrap? Just a long shot guess... Can anyone confirm/clarify?

[robmoss]

To provide you all with a little piece of mind, Linus himself is still using the 2.2.13 headers with whatever kernel he's got running. That's now two major revisions out of date, if he's using the 2.6 beta kernel, so you can assume that it's not only safe to use these headers, but in fact recommended practice by the man in charge!

With regards to the glibc bootstrap thing, I think that what happens is that the script compiles glibc, gcc, gettext and all the other essentials statically, which allows it to make self-contained binaries completely independent of everything else - no linking required, hence no glibc required. Then the headers are installed, then glibc, then gcc, then we get a working system. That's obviously not going to be completely accurate as I haven't studied it all with close scrutiny - but it's close enough!

[robmoss]

Oh, sorry - by statically, I mean that it uses glibc/headers etc. from the LiveCD, or whatever your install environment is, and compiles the relevant bits directly into the binaries.

[kyron]

To provide you all with a little piece of mind, Linus himself is still using the 2.2.13 headers with whatever kernel he's got running. That's now two major revisions out of date, if he's using the 2.6 beta kernel, so you can assume that it's not only safe to use these headers, but in fact recommended practice by the man in charge!

But....when recompiling glibc with the USE flag nptl enabled, it warns that you need a kernel that supports it ....2.6 ...So, somewhere along the line, you HAVE to switch referenced kernel headers to be able to go forward int he features world....or am I getting this all wrong?

[yardbird]

But....when recompiling glibc with the USE flag nptl enabled, it warns that you need a kernel that supports it ....2.6 ...So, somewhere along the line, you HAVE to switch referenced kernel headers to be able to go forward int he features world....or am I getting this all wrong?

Yes, you are absolutely right

[Forge]

bash-2.05b# emerge -epv world |grep linux-headers && emerge -epv world |grep glibc
[ebuild N ] sys-kernel/linux-headers-2.4.19-r1
[ebuild N ] sys-libs/glibc-2.3.2-r1 +nls -pic -build +nptl

It does build in nptl, running 2.6.0-test2-mm2.

It looks for *stable* headers in /usr/include/ and *current* headers in /lib/modules/*/build/include/.

[kyron]

bash-2.05b# emerge -epv world |grep linux-headers && emerge -epv world |grep glibc

Side note... You could get the results faster with bash-2.05b# emerge -epv world |grep -e "linux-headers" -e "glibc"

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kyron@kyron kyron $ emerge -epv world |grep -e "linux-headers" -e "glibc"
[ebuild  N   ] sys-kernel/linux-headers-2.4.19
[ebuild  N   ] sys-libs/glibc-2.3.2-r1  -nls +pic -build +nptl

[Forge]

I am now a wiser h4x0r. My mental grepping HOWTO is updated.

Danke.

[lodger]

Back in early Aug. I emerged linux-headers-2.4.19-r1 but
did not change over from 2.4.19 since I didn't know how or
why I should change it. (A little help here would be nice.)
I am thinking of moving to 2.4.20-gentoo-r6 from -r4 or even
trying the newer kernel but would like some info on the header
usage.
I am running ~x86 full time with gcc-3.2.3 and glibc-2.3.2-r1
and everything is smooth.
The move to -r6 is mainly for security reasons since the change logs didn't offer any compelling feature changes.
Thanks,
lodger