[CentOS] Multi-Card reader (SD, MMC, etc) and CONFIG_SCSI_MULTI_LUN kernel option in 34.0.2. Workaround

J.J. Garcia stigmatedbrain at gmail.com
Thu Aug 10 14:13:06 UTC 2006


El jue, 10-08-2006 a las 08:38 -0400, William Hooper escribió:
> J.J. Garcia wrote:
> > Hi folks,
> >
> >
> > Im trying to get a multi-card reader on centos (SD, MMC, and so, 4 card
> > slots) and i have read (http://www.cs.sfu.ca/~ggbaker/personal/cf-linux)
> > that CONFIG_SCSI_MULTI_LUN should be enabled on kernel (=Y) but current
> > 34.0.2 doesn't have it enabled by default, is there any particular
> > reason to not be enabled?
> 
> IIRC scanning LUNs freaks out some (real) SCSI hardware.  IIRC for Fedora
> they are creating a whitelist so that known OK devices are scanned.
> 

According to following link dated at November 98 i get this idea, don't
know if anybody has last news ... this is why i raised the question
http://www.uwsg.iu.edu/hypermail/linux/kernel/9811.3/0378.html

"When enabling both CONFIG_SCSI_MULTI_LUN and ide-scsi emulation, the
ATAPI devices will usually respond to every LUN. This can lead to an (as
yet untraced) oops."

And also in http://www.redhat.com/archives/rhl-beta-list/2004-
May/msg00235.html

Mentionning http://www.linuxjournal.com/article/6687

And http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=37935

I had no more time to check the actual patchlevel status in our kernel,
feel free to do it.

> > By the other hand i've also tweak the /etc/grub.conf file to boot the
> > kernel with max_luns=32 and results are the same, only scsc lun=0 is
> > recognized.
> >
> > At the same time using the workaround mentioned in the link pasted b4
> > regarding to modify the /etc/modules.conf to include 'options scsi_mod
> > max_scsi_luns=8' gives the same results, no detection at all for the card
> > slots.
> 
> Shouldn't that be max_luns=8, not max_scsi_luns=8 ?
> 
> 

I have no idea about it, if you follow the google links you will have
options for anybody in anyway, at least what i have found about it:

http://www.redhat.com/archives/rhl-beta-list/2004-May/msg00238.html

And also the main link i posted from Greg Baker:

http://www.cs.sfu.ca/~ggbaker/personal/cf-linux

If you have a better approach to do it, feel free to post it, this mail
was only my way to start up ideas with a single quick'n'dirty workaround
for me in this case ...

TIA

Jose.






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