From owner-freebsd-hackers Sat Sep 13 14:05:15 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id OAA29497 for hackers-outgoing; Sat, 13 Sep 1997 14:05:15 -0700 (PDT) Received: from usr08.primenet.com (tlambert@usr08.primenet.com [206.165.6.208]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id OAA29492 for ; Sat, 13 Sep 1997 14:05:10 -0700 (PDT) Received: (from tlambert@localhost) by usr08.primenet.com (8.8.5/8.8.5) id OAA20111; Sat, 13 Sep 1997 14:04:53 -0700 (MST) From: Terry Lambert Message-Id: <199709132104.OAA20111@usr08.primenet.com> Subject: Re: Do *you* have problems with floppies? To: dkelly@hiwaay.net Date: Sat, 13 Sep 1997 21:04:52 +0000 (GMT) Cc: Tor.Egge@idi.ntnu.no, hackers@FreeBSD.ORG In-Reply-To: <199709130622.BAA18777@nospam.hiwaay.net> from "dkelly@hiwaay.net" at Sep 13, 97 01:22:32 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > Any suggestions toward identifying FDC's with FIFO's? Preferably without > taking something apart? Augh. Read the code! The driver already does what little chip detection is possible! It uses the 0x10 command to identify the chip version. Only the Intel 82077AA has FIFO's (the 82078 des to, but I don't know what the heck it returns for a version ID -- anyone have one?). All other FDC chips with FIFO's are unprobeable, unless they return a version ID. When you boot, you will see one of: fdc0: NEC 765 fdc0: Intel 82077 fdc0: NEC 72065B fdc0: unknown IC type ff ...or *whatever* two digit hex value, other than 0x80, 0x81, or 0x90. The current driver code does not enable the FIFO. It would need to have detected as an 82077, and then use the Configure command (0x13) to clear bit 5 of command byte 2. It would set bits 0-3 to enable a 16 byte threshold. Then it would need to use the Lock FIFO command (0x94) to save the FIFO state across software resets. Then there would be additional code changes, as necessary, on top of that. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.