>From: ragge@ludd.luth.se
>Date: Tue, 2 Nov 1999 11:50:22 +0100 (MET)
>
>> Therefor I belive that the kernel has to issue some start command to
>> devices as it is probing the bus, RZ24 starts normally here but the
>> RZ56  does not.
>> Anders, could you look into this?
>> 
>I don't really know what to search for; my disks (RZ23 & RZ24) spins up
>when probed. I don't have a clue how the MI SCSI code handles this...

In /sys/dev/scsipi/sd.c:sdattach():

        error = scsipi_start(sd->sc_link, SSS_START,
            XS_CTL_DISCOVERY | XS_CTL_IGNORE_ILLEGAL_REQUEST |
            XS_CTL_IGNORE_MEDIA_CHANGE | XS_CTL_SILENT);

In /sys/dev/scsipi/scsipi_base:scsipi_start():

        return (scsipi_command(sc_link,
            (struct scsipi_generic *) &scsipi_cmd, sizeof(scsipi_cmd),
            0, 0, 2, (type & SSS_START) ? 30000 : 10000, NULL,
            flags));

As a wild guess, I would say that the timeout value of 30000 is too
small for the RZ56 to respond to the start unit command.

--
entropy