From owner-freebsd-scsi Wed Jan 29 12:23:45 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id MAA19161 for freebsd-scsi-outgoing; Wed, 29 Jan 1997 12:23:45 -0800 (PST) Received: from sendero.i-connect.net ([206.190.144.100]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id MAA19155 for ; Wed, 29 Jan 1997 12:23:42 -0800 (PST) Received: (qmail 7293 invoked by uid 1000); 29 Jan 1997 21:23:02 -0000 Message-ID: X-Mailer: XFMail 1.1-alpha [p0] on FreeBSD Content-Type: text/plain; charset=iso-8859-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 Date: Wed, 29 Jan 1997 12:55:07 -0800 (PST) Organization: iConnect Corp. From: Simon Shapiro To: freebsd-scsi@freebsd.org Subject: XXXminpys question Sender: owner-freebsd-scsi@freebsd.org X-Loop: FreeBSD.org Precedence: bulk When/how is the minphys entry point in an HBA driver called? All we see in the bt and ahc drivers is a comparison between a buf and a constant. In the driver we are writing now, mulltiple controllers, all run with the same driver, can EACH have their own minphys. Actually, like others, it is limited by the scatter-gather DMA engine. The cheapest HBA can have 16 segments in the DBA S/G. The largest can have 8192 currently. May grow larger. What we need, in addition to the clarification above is these answers: a. Does minphys get called for each I/O request, with that I/O's own buf? b. Does minphys get called, at initialization time, once per HBA? c. Does minphys get called only once for ``the driver''? If A is true, we can (nasty) extract the HBA from the device data in buf. If B is true, we need some indication in calling minphys as to which HBA. Ic C is true, we have a problem. In that case, can we manipilate the buf structure when the SCSI command is called in and do only partial I/O by manipulating the b_count and b_resid fields? This is sort of a stalling stump for us so soon response will be appreciated... Thanx! Simon