installer cannot find SAS SCSI CD-ROM

[Alexandru Munteanu <io_fx@yahoo.fr>]

Hello,

the debian installer fails to find the CD-ROM (and thus to mount it)
on a system having a 'Fusion MPT SAS Host' controller with a SCSI CD-ROM.

The linux kernel module needed for the debian installer to detect and mount
the CD-ROM is 'mptsas', which apparently is not included in the linux image
at boot time.

Here is a workaround hack of how to get the installer to "work" :

  Copy the scsi-* 'udeb' files to a usb key :

  * mount the debian ISO :
    $ mount -o loop debian_image.iso /media/cdrom
  * mount the USB key :
    $ mount /dev/sdb1 /media/usb1
  * copy the scsi* udeb files :
    $ cp $(find /media/cdrom/ -name "*scsi*.udeb") /media/usb1/
    $ cd /media/usb1
  * extract the scsi debian packages :
    $ for a in *.udeb;do dpkg -x $a;done
  * create a .tar.gz archive :
    $ tar czf lib_scsi_sas.tar.gz lib
  * unmount the usb key
    $ umount /media/usb1

  Boot with the Debian CD :

  * switch to console 2 with Ctrl+Alt+F2 and then press enter
  * mount the usb key :
    $ modprobe vfat
    $ mkdir /mnt/usb1
    $ mount /dev/sde1 /mnt/usb1
    $ cd /mnt/usb1/
  * extract the SCSI and SAS modules :
    $ tar zxf lib_scsi_sas.tar.gz -C /
  * update modules dependencies :
    $ depmod
  * load the required module :
    $ modprobe mptsas
  * verify that the cd-rom is recognised :
    $ dmesg | tail -n 30 | grep "CD-ROM"
    ...
    Uniform CD-ROM driver Revision: 3.20
    sr 10:0:0:0: Attaches scsi CD-ROM sr0
  * you can test by mounting the cdrom :
    $ mkdir /mnt/cdrom && mount /dev/sr0 /mnt/cdrom
    $ ls /mnt/cdrom/ && umount /mnt/cdrom
  * unmount the usb stick :
    $ cd / && umount /mnt/usb1
  * switch to console 1 (debian installer) with Ctrl+Alt+F1 and choose
   ("No", "No", "Continue") "Detect and mount CD" (from the main menu)

Best regards,
-- 
Alexandru Munteanu