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Re: ide-scsi emulation and modules configuration at



On Fri, Dec 17, 2004 at 12:19:20AM +1100, Ivan Teliatnikov wrote:
> What is for
> max_scsi_luns=1
> 
> System has internal SCSI drive and 2 IDE cdroms. What should be a
> max_scsi_luns?

from /usr/share/doc/HOWTO/en-txt/BootPrompt-HOWTO.gz
(one of the ldp howtos, in the doc-linux-text package):

  6.1.1.  Maximum Probed LUNs (`max_scsi_luns=')

  Each SCSI device can have a number of `sub-devices' contained within
  itself. The most common example is any of the SCSI CD-ROMs that handle
  more than one disk at a time.  Each CD is addressed as a `Logical Unit
  Number' (LUN) of that particular device. But most devices, such as
  hard disks, tape drives and such are only one device, and will be
  assigned to LUN zero.

  The problem arises with single LUN devices with bad firmware.  Some
  poorly designed SCSI devices (old and unfortunately new) can not
  handle being probed for LUNs not equal to zero. They will respond by
  locking up, and possibly taking the whole SCSI bus down with them.

  The kernel has a configuration option that allows you to set the
  maximum number of probed LUNs. The default is to only probe LUN zero,
  to avoid the problem described above.

  To specify the number of probed LUNs at boot, one enters
  `max_scsi_luns=n' as a boot arg, where n is a number between one and
  eight. To avoid problems as described above, one would use n=1 to
  avoid upsetting such broken devices
  6.1.2.  SCSI Logging (`scsi_logging=')

  Supplying a non-zero value to this boot argument turns on logging of
  all SCSI events (error, scan, mlqueue, mlcomplete, llqueue,
  llcomplete, hlqueue, hlcomplete).  Note that better control of which
  events are logged can be obtained via the /proc/scsi/scsi interface if
  you aren't interested in the events that take place at boot before the
  /proc/ filesystem is accessible.


I have it set to 1, I think that is right unless you have a cdrom jukebox or
something.

> initrd          /initrd.img-2.4.26-1-686
> savedefault
> boot
> 
> Lsmod shows that after reboot both cdrom and ide-cd modules are running

You don't want ide-cd loaded, just sg and ide-scsi,
put them in your /etc/modules file.

> Could this be because I have discover1 installed or something similar
> that tries to reconfigure my kernel modules?

Maybe that's the trouble, I don't use it.

I suggest once you've "discovered" what modules you need for your system,
disable discover and specify them manually in /etc/modules.



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