AIC7XXX oddities

AIC7XXX oddities

[e-double]

Greetings,
I've been using the new aic7xxx driver, and updating frequently from Justin's site.  I'm at v6.1.11 now with kernel 2.4.3 and still experiencing some odd behaviour.  For example, I start as such on BUS 0 (an aic-29160):
Channel A Target 5 Negotiation Settings
        User: 160.000MB/s transfers (80.000MHz DT, offset 255, 16bit)
        Goal: 160.000MB/s transfers (80.000MHz DT, offset 63, 16bit)
        Curr: 160.000MB/s transfers (80.000MHz DT, offset 63, 16bit)
        Channel A Target 5 Lun 0 Settings
                Commands Queued 13199
                Commands Active 0
                Command Openings 49
                Max Tagged Openings 253
                Device Queue Frozen Count 0
After an invocation of cdrecord --scanbus
dmesg reveals this on BUS1 (an aha-2940u2w):
(scsi1:A:1): 5.000MB/s transfers (5.000MHz, offset 15)
(scsi1:A:6): 20.000MB/s transfers (20.000MHz, offset 15)
(locating burner at 6, and zip at 5)

An invocation of hdparm -Tt /dev/sda (id 5) does this:

(scsi1:A:1): 5.000MB/s transfers (5.000MHz, offset 15)
(scsi1:A:6): 20.000MB/s transfers (20.000MHz, offset 15)
(scsi0:A:5): 3.300MB/s transfers

cat /proc/scsi/aic7xxx/0 :
Channel A Target 5 Negotiation Settings
        User: 160.000MB/s transfers (80.000MHz DT, offset 255, 16bit)
        Goal: 3.300MB/s transfers
        Curr: 3.300MB/s transfers
        Channel A Target 5 Lun 0 Settings
                Commands Queued 16817
                Commands Active 0
                Command Openings 49
                Max Tagged Openings 253
                Device Queue Frozen Count 0

Target 5 has dropped to 3.300MB/s ??

thanks,

Ethan W.


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Re: AIC7XXX oddities

[Justin T. Gibbs]

>An invocation of hdparm -Tt /dev/sda (id 5) does this:
>
>(scsi1:A:1): 5.000MB/s transfers (5.000MHz, offset 15)
>(scsi1:A:6): 20.000MB/s transfers (20.000MHz, offset 15)
>(scsi0:A:5): 3.300MB/s transfers

The situation might be clearer if you run with aic7xxx=verbose.
My guess is that the target detected a CRC error a transaction
and negotiated async as an indication that the initiator should
perform domain validation on this bus segment again.  Unfortunatly,
the driver doesn't yet support domain validation, so you end up
being stuck at 3.3MB/s.  I would suggest looking for problems with
your cabling or termination on that controller.

--
Justin