Subject: MI-SCSI question
To: None <tech-kern@NetBSD.ORG>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
Date: 02/04/1997 23:20:15
I got back to working on the sc driver for the sun3 port. This is a
SCSI interface that is amazingly dumb in some ways. In particular, it
simply cannot deal with cdbs other than 6 bytes long.
I turned on a bunch of debugging, and see the following sequence when I
boot my test kernel (summarized):
command: 00 00 00 00 00 00 (TEST_UNIT_READY) -> 0 bytes transferred
command: 12 00 00 00 2c 00 (INQUIRY) -> 44 bytes transferred
output: sd2 at scsibus1 targ 1 lun 0 <...>
command: 1b 00 00 00 01 00 (START_STOP) -> 0 bytes transferred
command: 1a 00 04 00 20 00 (MODE_SENSE) -> 46 bytes transferred
output: sd2(sc0:1:0) 680 cyls, 5 heads, 0 precomp, 0 red_write, 0 land_zone
command: 25 00 00 00 00 00 00 00 00 00 (READ_CAPACITY) -> failure
(of course, since it's 10 bytes, not 6 bytes, long)
output: sd2(sc0:1:0): could not get size
output: 0MB, 680 cyl, 5 head, 0 sec, 512 bytes/sec x 0 sectors
Now I'm _sure_ I saw some commit messages indicating that the MI SCSI
subsystem no longer depended on non-6-byte commands, so why is it
falling over when a 10-byte command fails? Am I doing something wrong?
I sure _thought_ those were pre-1.2 commits, and this is a 1.2 kernel
tree I'm working with. Do I need to set some quirk? (I didn't see
anything promising when looking at the list of quirks.) Or is the real
mistake here my canning things when I saw the message claiming the
thing had zero sectors, and it actually would have worked fine anyway?
I have full dmesg output, in case anyone wants to see it. Some of the
debugging gunk is specific to my driver, but not all.
7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B