CDROM found in /proc/scsi/scsi but no /dev entry. Trying to make livecd.

simonb · 11-28-2008, 09:16 AM

I am trying to debug the Mandriva 2009 mklivecd script. It's well known that it has been broken for some time so I am attempting to bring it up to date because I need it to work. I am using kernel 2.6.27.5-desktop-2mnb.

When I boot the ISO in VirtualBox it loads all the modules OK but can't find the cdrom. I suspect there is some module I have missed out but can't guess what it is.

The CDROM ISO is presented as an ide device by VirtualBox (i.e. I'm not doing anything unusual) and appears to be detected as a SCSI device.

I have also attached a virtual IDE disk but that also doesn't show up in /dev.

Code:

cat /proc/scsi/scsi
Attached devices:
Host: scsi1 Channel:00 Id: 00 Lun: 00
  Vendor: VBOX  Model: CD-ROM  Rev: 1.0
  Type:   CD-ROM               ANSI SCSI

Code:

lsmod (only modules and used by listed since I have no copy/paste from terminal)
Module			Used by
3w_xxxx			Live
usb_storage		Live
ehci_hcd		Live
ohci_hcd		Live
uhci_hcd		Live
usbcore			usb_storage,ehci_hcd,ohci_hcd,uhci_hcd, Live
i2c_piix4		Live
i2c_core		i2c_piix4, Live
scsi_transport_sas	Live
ide_scsi		Live
ide_core		ide_scsi, Live
isofs			Live
mptbase			Live
sd_mod			Live
crc_t10dif		sd_mod, Live
sr_mod			Live
loop			Live
ata_piix		Live
ahci			Live
libata			ata_piix,ahci, Live
scsi_mod		3w_xxxx,usb_storeage,scsi_transport_sas,ide_scsi,sd_mod,sr_mod,libata, Live
dock			libata, Live

Code:

ls /dev
core	fd	null	pts	stderr	stdin	stdout

simonb · 11-29-2008, 04:05 AM

OK. I'm answering my own post here :-)

The problem turned out to be that udev has depreciated the udevstart command that the initrc script was using to generate the device nodes.

Getting it to work with Mandriva 2009 involves using the start_udev script. This in turn depends on /etc/rc.d/init.d/functions being present which doesn't work with busybox's ash so bash and it's libraries also need to be copied.

Once the new udev start script is happy then the CDROM is available as /dev/sr0 as expected.

I now have a working Live CD so I have posted the patches to this bug report.
https://qa.mandriva.com/show_bug.cgi?id=46068