Arch Linux

mackstevenson

Member

Registered: 2005-04-14

Posts: 18

cdrom drive detected but inacessible

Hi all

Ever since I installed arch I'm experiencing the following strange problem:

- I am using udev

- I can boot from the arch linux cd without any problems

- dmesg shows

hdc: CD-224E, ATAPI CD/DVD-ROM drive

-but I can't access my cd drive. If I try to mount /dev/hdc, I get a "" error. (And it is indeed true that the device file isn't there.)

How can I solve this? Why does my system see and not see the drive?

Thank you for any tip,

Mack

T-Dawg

Forum Fellow

From: Charlotte, NC

Registered: 2005-01-29

Posts: 2,736

Re: cdrom drive detected but inacessible

did you create the proper directory in /mnt/ ? Compare your fstab and make accordingly. Also you should add yourself to the proper groups to have access to it. Check the wiki for the groups. I think recomended is floppy,audio,optical,storage,video, and scanner...gpasswd -a username audio   etc.

phrakture

Arch Overlord

From: behind you

Registered: 2003-10-29

Posts: 7,879

Website

Re: cdrom drive detected but inacessible

don't use hdc - udev understands it's a cdrom and creates a /dev/cdroms/cdrom0 device...

make sure to add your user to the "optical" group to use optical drives...

then just do "mount /mnt/cd" and it should work fine (assuming your /etc/fstab is setup right)

---

http://phraktured.net

mackstevenson

Member

Registered: 2005-04-14

Posts: 18

Re: cdrom drive detected but inacessible

don't use hdc - udev understands it's a cdrom and creates a /dev/cdroms/cdrom0 device..

I only tried /dev/hdc because that's just what shows up in dmesg/while booting. But what I can't understand is why while the system is up neither /dev/hdc nor /dev/cdroms/cdrom0 exist. [Actually, /dev/cdroms itself doesn't exist, for that matter.]

make sure to add your user to the "optical" group to use optical drives...

Thank you for the tip, but unfortunately I just did that, rebooted and nothing changed. To make sure it's not a problem of permissions I also logged in as root and the problem persists.

did you create the proper directory in /mnt/?

/mnt existed since I first installed arch. What I am trying is

# mount -t iso9660 /dev/hdc /mnt

and

# mount -t iso9660 /dev/cdroms/cdrom0 /mnt

and in both cases it fails because neither of those devices exist. I googled and this seems to be the right command. Why isn't udev creating the devices?

I'd greatly appreciate any tip on how I may correct this. Other than this everything works great! Eg, even sound works without a problem.

- Mack

phrakture

Arch Overlord

From: behind you

Registered: 2003-10-29

Posts: 7,879

Website

Re: cdrom drive detected but inacessible

hmmm - what kernel are you running... are you sure you're running udev? (check ps aux)

---

http://phraktured.net

mackstevenson

Member

Registered: 2005-04-14

Posts: 18

Re: cdrom drive detected but inacessible

Thank you for your ongoing help:

# uname -a
Linux comp1 2.6.10 #11 Tue Apr 19 22:25:49 EDT 2005 i686 Mobile Intel(R) Pentium(R) III CPU - M  1200MHz GenuineIntel GNU/Linux

[root@comp1 etc]# pidof udevd
783

(I assume it's udevd, rather than udev, that should be running; is this correct? Anyway I also tested udev and it is *not* running.)

If it is any good, after the kernel finishes booting arch prints "Starting udev daemon.... [Done]" and then "udev startup is finished!"

Just for reference, this is a "multi" drive that burns cds/dvds; I noticed the top of the /etc/udev/cdsymlinks.sh file mentions "preferences" concerning the names given to the devices depending on whether or not they are dvd-readers and/or burners.

This is my /dev:

[root@comp1 udev]# ls /dev/
adsp      discs  hda3     kmsg    psaux  ram12  ram5    shm     tty    ttyS6
agpgart   dsp    hda4     legacy  ptmx   ram13  ram6    snd     ttyS0  ttyS7
apm_bios  fd     i830     mem     pts    ram14  ram7    sound   ttyS1  urandom
audio     full   ide      misc    ram0   ram15  ram8    stderr  ttyS2  vc
console   hda    initctl  mixer   ram1   ram2   ram9    stdin   ttyS3  vcc
core      hda1   input    null    ram10  ram3   random  stdout  ttyS4  zero
cpu0      hda2   kmem     port    ram11  ram4   rd      tts     ttyS5

However, again,

# dmesg|grep -i cd
hdc: CD-224E, ATAPI CD/DVD-ROM drive

What is udev doing to my system? Why doesn't it create the necessary symlinks?

Thank you for any help,

Mack

PS: As I mentioned previously (and have just tested), putting the arch 0.7 install cd and into the drive and booting works flawlessly... Can you make sense of this???

mackstevenson

Member

Registered: 2005-04-14

Posts: 18

Re: cdrom drive detected but inacessible

Hi again!

Just found out that for some reason the required ide_cd and cdrom modules were *not* being loaded; running

# modprobe ide_cd

solved it, ie, /dev/cdroms/cdrom0 and /dev/hdc were immediately created. I confirm that tan now mount/unmount those partitions. Why aren't these loaded automatically?

Actually, this is something thidalways counfounded me when using other distros: basically, it seemed compleyely unpredictable when a necessray module  was automatically loaded andwhether you must configure it

Hopefully more of you will weight in and ofter clever suggestions,

Best for now,

Mack

T-Dawg

Forum Fellow

From: Charlotte, NC

Registered: 2005-01-29

Posts: 2,736

Re: cdrom drive detected but inacessible

hotplug should have picked it up but I guess it doesn't always. You can add that module to the MODULES() array in rc.conf to load it next time at boot.

mackstevenson

Member

Registered: 2005-04-14

Posts: 18

Re: cdrom drive detected but inacessible

Thank you all for your help, after all this is just hotplug forgetting to load the necessary modules.

- Mack