Date: Thu, 27 Sep 2001 17:11:53 -0400 (EDT) From: Michael Giovinco <gio@actuality-systems.com> To: aic7xxx@FreeBSD.ORG Subject: Wide and Synchronous transfers in Linux Message-ID: <Pine.LNX.4.10.10109271659120.27895-100000@jigglypuff.actuality-systems.com>
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Hello, I have a external (target) SCSI device that I've built and I've been trying to get it to work under Linux using the generic (sg) driver. The host computer that I am using has a Adaptec 29160 SCSI card in it so I am using the AIC7XXX driver in a 2.4.9 version kernel (slackware, if anyone cares). The device uses a LSI SYM875 chip if anyone cares. So far everything is going great - except that I am unable to get wide or synchronous transfers to work. Thus, my transfers are very slow (both the "goal" and "current" are listed as 3.30 MB/s according to /proc/scsi/aic7xxx/0). The device had previously been running under Windows NT where I learned that NT will negotiate wide and synchronous transfer if the inquiry data it receives affirms that the target device is capable of them. I have yet to see the Linux driver attempt to negotiate a wide or synchronous transaction so I took it upon myself to try - namely, have my target device do the negotiation. The host computer responds with the correct protocol, except it always responds with "narrow" when I ask for "wide", and it responds with zero for the period and offset when I request specific values (80ns offset and 16 offset is what I'd like to use). It appears to know that my host adaptor is capable of this (it says Ultra160 Wide Channel A etc in /proc/scsi/aic7xxx/0). What do I have to do, or have my target device do, to convince it to perform wide and synchronous transfers? I've been digging through the aic7xxx driver code and I can't figure out where it is going wrong. Is there something special I need to put in the inquiry data returned? Or is the some boot parameter I need to give the driver? I'd appreciate any help anyone could give me on this matter. Thanks. Mike gio@actuality-systems.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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