Re: HBA self selection

[Douglas Gilbert <dougg@torque.net>]

Cameron, Steve wrote:
> Noticed in scsi_scan.c (2.6.15.2 kernel...)
> 
>    1336 static void __scsi_scan_target(struct device *parent, unsigned int chann        el,
>    1337                 unsigned int id, unsigned int lun, int rescan)
>    1338 {
>    1339         struct Scsi_Host *shost = dev_to_shost(parent);
>    1340         int bflags = 0;
>    1341         int res;
>    1342         struct scsi_target *starget;
>    1343
>    1344         if (shost->this_id == id)
>    1345                 /*
>    1346                  * Don't scan the host adapter
>    1347                  */
>    1348                 return;
>    1349
> 
> There exist some target devices which depend on the adapter being
> able to do self selection.  The HP MSA30 presents a processor device
> at ID 7, for instance.
> 
> The processor device at ID 7 will generally not be accessible, because
> the HBA is generally at this ID.  The processor device doesn't care that the
> HBA is at id 7.  He says, "hmm, the adapter is talking to himself,
> that means, he's talking to me."   It's just a way to put a processor
> device on the bus without really "using up" a scsi id, since there
> are only a few of them.
> 
> This used to work, I'm pretty sure.  Could do 
> "echo scsi add-single-device 0 0 7 0 > /proc/scsi/scsi" and 
> the processor device would show up.  Now it doesn't.

Steve,
I suppose the lk 2.6 equivalent of:
# echo "0 7 0" > /sys/class/scsi_host/host<n>/scan
doesn't work either? [The reason I ask is that the
new technique works for finding "well known" lus.]

Doug Gilbert