So, I downloaded and reinstalled the modules, headers and source for 2.6.18 from /testing. I took them from the slack repository in slackware.com. However, the problem still exists. Sometimes after reboot I have sound, and sometimes I have no sound with the message:

Error while initializing the sound driver:
device: default can't be opened for playback (No such file or directory)
The sound server will continue, using the null output device.

When I have no sound, I have no sound outside X too (I have some players that do not need X to run).

My sound card is:
00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 02)

I have really no idea what that weird behaviour of test26.s can be due to. With generic-2.6.18 I never have such a problem.

Thank you for your attention.
Regards,
Martin

My current practice is rebooting several times until sound comes. I do not think this is normal, is it?

I'm not a senior member yet

you should compare the two config files to see what the difference is

It is very unusual for Linux to randomly work or not.
This could be the bios messing things up, irq clashes or maybe you have a second sound device like a video capture card or a modem

Obviously my case is exactly this.
I am not a computer expert, I am just an ordinary linux fan, and still I am a newbie . Could you please tell me how to check whether bios is messing something? How to check whether there are irq clashes? And what is irq? I would be thankful if you recommend to me some literature on irq I do not have a modem for certain. How can I check whether I have some other sound device, apart from my
00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 02)

This very problem only exists with the test26.s, not with the generic kernel. In some other forum they recommended to me to make the symlink rc.modules in /etc/rc.d point to rc.modules-2.6.18 instead of rc.modules-2.4.33.3. I did that too, and yesterday again there was a reboot after which I had no sound. So this does not seem to be the solution either.
Since I am still a newbie in Linux I would be thankful to you if you tell me what exactly I should look for in the config files?

Thank you very much for your attention and responsiveness.
Regards,
Martin.

After installing the new kernel did you update the modules with
Before rebooting the machine

Also I found I needed to edit my /etc/fstab to mount sysfs and a few other things to allow the new 2.6 kerenls to work properly

Thank you very much for your reply. So I ran "depmod -a 2.6.18", edited /etc/fstab the way you pointed. Now that part of my /etc/fstab is:
none /mnt/ramfs tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
proc /proc proc defaults 0 0
usbfs /proc/bus/usb usbfs devgid=14,devmode=0660 0 0
sysfs /sys sysfs defaults 0 0

I notice the difference with tmpfs and options of devpts the between the default fstab and the one you posted? I appended the lines about usbfs and sysfs, but I did not dare to change the lines with tmpfs and devpts
After I rebooted I got the favourite message of problem with sound drive and I had no sound, of course . So I rebooted and then I had sound. So this is not the solution. The weird behavoiur of test26.s on my system goes on.
However, this time I read carefully some kernel messages at booting. I noticed the following:
Jan 16 18:02:52 marto kernel: ICH4: not 100%% native mode: will probe irqs later

and further down concerning the irqs, this is the only line mentioning irq, that complains about something. The other irq lines seem to say ok:

Jan 16 18:02:52 marto kernel: qlogicfas: no cards were found, please specify I/O address and IRQ using iobase= and irq= options<6>QLogic Fibre Channel HBA Driver

I hope that this will shed some more light on the problem.
Thank you very much for your attention.
Regards,
Martin

I think I have found the problem, I grab the 2.6.18 kernel sources from my slackware dvd and checked out how the kernel is configured throught make xconfig, the kde graphical frontend to recompiling the kernel. It looks like that sysfs is not enables/supported in the kernel, this means that all the devices that are detected during the boot process are not being created through udev and hotplug.

This would be the reason that you are not finding your audio deviece and using the null output, it basically not there. So having those entries in the fstab file wont make a difference at the moment. I have had the same trouble with sound over the last couple of weeks when I was recompiling my kernel for the livecd that I am making. Once I found that the sysfs was not built into the kernel, I just enables it and then added those entries to the fstab and I know have full sound on no matter what computer I boot from.

I see. So the question now is how do I enable sysfs?

Thank you for your responsiveness.
Regards,
Martin

The only way would be to recompile the kernel and add support for the sysfs. To so this you will need install the source file from, disc 2 i think: /testing/packages/linux-2.6.18/kernel-source-2.6.18-noarch-1.tgz if you already haven't done so.

Follow these steps:

step 1. cd /usr/src/linux-2.6.18
step 2. step make mrproper
step 3. make xconfig

This will open the kde graphical menu for kernel configuration, on the left window at the top look for General Setup, just under it you should tick Configure standard kernel features (for small systems). When you tick it on the right hand side you should see some more option appear, just make sure all these are ticked as well

Then on the left side down near the bottom look for File systems, just under this you should see Pseudo filesystems. Left mouse click on the Pseudo filesystems will then open some options on the righthand side, you need to make sure that 4 are ticked:

/proc file system support
/proc/kcore support
/sysfs file system support
Virtual file system support (former shm fs)

Once tht is done you can have a look around and see if you need anything else, if not just exit out, it will then ask you to save, say yes, then continue with the next steps

step 4. make
step 5. make modules
step 6. make modules_install
step 7. make install <--- need this to install kernel and will update lilo
step 8. depmod -a 2.6.18


Then reboot with the entries in fstab and hopefully everything should now work. It may take quite a while to compile the kernel, my 1.8 ghz takes about an hour or so.

Actually, with the 2.6 series kernels, 'make' makes the kernel AND the modules, so 'make modules' is an unnessecary step.

Also, "make modules_install" has NOTHING to do with lilo. lilo is another ball of wax. Please do not confuse the issue.

There are MANY threads in the Slackware forum to address compiling kernels
.

This discussion is WAY off topic.

All this thread is for is to have a place to tell people to install the modules in /testing or /extra, not how to compile a kernel.

Ok, but does this mean that sysfs support is compiled in the generic kernel? I have had no sound problems with it at all.

Regards,
Martin

OK, I think my question is relevant to this thread, because I just want to install the 2.6 kernel - so I won't start a new one. I've got a stable Slack 11.0 box set up (ie. I don't want to be experimenting & breaking things). However, I would like to upgrade from the 2.4 to huge26 (2.6.17.13) kernel. I've read the files and looked at threads like this, but I want to make sure I've got the process right so I don't mess up my computer.

So, can I just use these steps?
1) install kernel-generic-2.6.17.13-i486
2) install kernel-modules-2.6.17.13-i486
3) edit bootloader to point to right kernel (and back up 2.4 kernel in case something goes wrong)
4) reboot & run new kernel

Are there any steps I'm missing? Just switching the kernel like that shouldn't mess up all my compiled programs and my whole setup, right?

Thanks for any tips you can give.

see i was really confused with the testing kernel shipped with slack once.

for me there is no /testing dir in 2nd cd, but there is one in 3rd cd tht didnt include kernel, so i skipped testing the test kernel

i downloaded the 3 cds from net.
http://rkrishna.tp.googlepages.com/slackerbasics#alt

dont use upgradepkg

[QUOTE][back up 2.4 kernel in case something goes wrong/QUOTE]no backing up, just adding stuffs to lilo and to /boot. once it is finalised, if you want u can remove old kernel stuffs

regards