kernel 2.4 2.6 upgrade & cd-rom

Quercus ruber · 10-26-2006, 03:04 AM

Hi

I have just upgraded from the standard slack 2.4.31 kernel to 2.6.16.24 because I wanted support for our new digital camera. I compiled it myself (first new kernel and I had to do it several times before I got it right), so I spose its a custom kernel.

Hitherto I'd been using scsi emulation for the cdrom drive:

Code:

image = /boot/vmlinuz-ide-2.4.31
  append="hdc=ide-scsi"
  root = /dev/hda5
  label = Linux
  read-only

#2.6.16.24
image = /boot/vmlinuz-2.6.16.24
  root = /dev/hda5
  label = test
  read-only

But I've read in many places that this is no longer required, so the line is not there for the 2.6 kernel.

However, now my cdrom drive seems to have disappeared.

When I say disappeared, I mean I get this error message when I try to mount it from the command line:

Code:

family@Einstein:~$ mount /mnt/cdrom
mount: I could not determine the filesystem type, and none was specified
family@Einstein:~$

And xine says that it can't find a drive containing a dvd.

It all works fine when I boot with the 2.4 kernel. I've read a great deal about this over the last few days, and I've ascertained that its to do with the scsi emulation that 2.4 had. Its left some symlinks that are no longer required, but I haven't been able to work out which ones have to go. Here is some info that might be helpful:

Code:

family@Einstein:~$ dmesg |grep CD
hdc: AOPEN COM4824/AAH, ATAPI CD/DVD-ROM drive
hdc: ATAPI 48X DVD-ROM CD-R/RW drive, 2048kB Cache, UDMA(33)
Uniform CD-ROM driver Revision: 3.20
family@Einstein:~$

Code:

family@Einstein:~$ cat /etc/fstab
/dev/hda6        swap             swap        defaults         0   0
/dev/hda5        /                reiserfs    defaults         1   1
/dev/hda7        /home            ext3        defaults         1   2
/dev/hda1        /ntfs            ntfs        user,umask=000,ro,auto    1   0
/dev/hdb1        /fat-e           vfat        user,umask=000,rw,auto    1   0
/dev/cdrom       /mnt/cdrom       auto        noauto,user,unhide,ro     0   0
/dev/fd0         /mnt/floppy      auto        noauto,owner     0   0
/dev/sda1       /mnt/camera       vfat        noauto,user       0   0
devpts           /dev/pts         devpts      gid=5,mode=620   0   0
proc             /proc            proc        defaults         0   0
family@Einstein:~$

I feel a bit silly about this; praps I put the wrong keywords in the search engines. I find it quite annoying when a topic closes with something along the lines of "I've solved the problem - it was a simlink all along - thanks for your help" and then never actually say what the problem was or how it was solved.

ros

Quercus ruber · 10-26-2006, 07:11 AM

hi

I believe I have solved my problem.

My links were thus:

Code:

family@Einstein:~$ ls -l /dev/hdc
brw-rw-rw-  1 root disk 22, 0 2002-06-09 21:27 /dev/hdc
family@Einstein:~$ ls -l /dev/cdrom
lrwxrwxrwx  1 root root 8 2006-03-30 12:25 /dev/cdrom -> /dev/sr0
family@Einstein:~$ ls -l /dev/sr0
brw-rw-rw-  1 root cdrom 11, 0 1999-04-13 06:24 /dev/sr0

I changed them thus:

Code:

root@Einstein:/dev# rm cdrom
root@Einstein:/dev# ln -s /dev/hdc /dev/cdrom
root@Einstein:/dev#

And now I can mount

Code:

family@Einstein:~$ ls -l /dev/cdrom
lrwxrwxrwx  1 root root 8 2006-10-26 13:03 /dev/cdrom -> /dev/hdc
family@Einstein:~$ mount /mnt/cdrom/
family@Einstein:~$ ls /mnt/cdrom/
Autorun.inf*  Games/  SDL.dll*  SDL_mixer.dll*  Start.exe*  System/  UnzDll.dll*  ogg.dll*  vorbisfile.dll*
family@Einstein:~$

ros

manwichmakesameal · 10-27-2006, 12:38 PM

I couldnt tell if you did this or not, but when you switch from 2.4.* to 2.6.* the scsi emulation isnt needed anymore. You should use "ide-cd dev=/dev/hdc" now instead of "hdc=ide-scsi". I think its only really important if your hdc is a burner device though I could be wrong.

johnson_steve · 10-27-2006, 01:37 PM

I think the reason why your links were wrong was:

Quote:

* As of 2.6.13 the support for devfs has been removed.
* You will be required to either manage a static /dev
* or to ensure that udev is starting on boot.

So your old kernel used devfs but the new one doesn't and you don't have udev. so all of your /dev stuff is from the old kernel and not the new one. You will have to manage /dev yourself (like fixing the link you just fixed) or install udev.