[6147] in linux-scsi channel archive
Q: aha152x and 7502 CDR
daemon@ATHENA.MIT.EDU (Nathan Hand)
Mon Mar 22 09:30:16 1999
Date: Tue, 23 Mar 1999 01:05:48 +1100 (EST)
From: Nathan Hand <nathanh@wookie.chirp.com.au>
Reply-To: Nathan Hand <nathanh@wookie.chirp.com.au>
To: linux-scsi@vger.rutgers.edu
I've posted recent messages regarding problems with a 7502 causing the
aha152x driver to kernel panic (while reading via dd). I'm now looking
at the code generating the panic. The segment is as follows.
case P_CMD: /* command phase */
...
SETPORT(SIMODE0, 0);
SETPORT(SIMODE1, ENPHASEMIS|ENREQINIT|ENBUSFREE);
/* wait for data latch to become ready or a phase change */
while(TESTLO(DMASTAT, INTSTAT))
barrier();
for(i=0; i<CURRENT_SC->cmd_len && TESTLO(SSTAT1, PHASEMIS); i++) {
SETPORT(SCSIDAT, CURRENT_SC->cmnd[i]);
make_acklow(shpnt);
getphase(shpnt);
}
if(i<CURRENT_SC->cmd_len && TESTHI(SSTAT1, PHASEMIS))
aha152x_panic(shpnt, "target left COMMAND");
As I understand this code, an interrupt for PHASEMIS is set and a busy
loop writes the cmd_len command bytes to a data port. For my command I
believe I have 6 command bytes, because cmnd=(Read (6) 00 02 91 08 00)
is in the current_SC section of the kernel panic dump. If any of these
command bytes result in the PHASEMIS going HIGH, something broke.
Now the read arguments appears to have been "00 02 91 08 00", and this
has been verified by multiple kernel panics (they can be produced very
consistently). My question is, is the PHASEMIS being brought high by a
device on the SCSI bus, or by the card itself? In other words, would I
get the same fault with a different card, or is this 1505 specific?
Is it even correct to kernel panic if PHASEMIS goes high during a cmnd
write? I would have thought that though it indicates a failure, surely
it's not so bad that the system should hang. I don't see similar panic
code for any of the other SCSI controller drivers.
As I've said in previous posts, I don't think this is a termination or
hardware problem. The same gear works great in Windows 95, though I am
aware this isn't proof positive of OK gear, but I've gone over it with
a fine toothed comb, changing cables and the like.
I have subscribed myself to the linux-scsi mailing list and received a
confirmation email, but I'm not seeing any traffic. Please CC: replies
directly to me in addition to the mailing list, thank you.
--
Nathan Hand - Chirp Web Design - http://www.chirp.com.au/ - $e^{i\pi}+1 = 0$
Phone: +61 2 6230 1871 Fax: +61 2 6230 4455 E-mail: nathanh@chirp.com.au
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