From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: To: 9fans@9fans.net Date: Sat, 30 Aug 2008 07:05:30 +0200 From: lucio@proxima.alt.za In-Reply-To: <3df301650808291825m2e9db4a0hd0f810ff60201e25@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] 3c509b troubles Topicbox-Message-UUID: 0b7192c8-ead4-11e9-9d60-3106f5b1d025 > heh. geez am i dopey. the problem was my misunderstanding of what the > irq=xx parts in plan9.ini do. bios decides the irq, plan9.ini tells > the kernel what the bios decided. that's my isa card mantra from now > on I was going to suggest you base your configuration on what OpenBSD determines. It I remember right (I have a few 3Com cards I treasure) they all allowed an autoconfiguration that predates PnP but resembles it somehow: identify the autoconfiguration port and wiggle it to tell the card where to enable IRQ, I/O and possibly DMA. Plan 9 may have had an issue with the configuration port. ISA has a big issue with shared IRQs: IBM engineered the IRQs to be level-triggered and active low TTLs, so an inactive card would mask any other card reporting an interrupt on the same line. I was told some of these decisions (the choice of 8250s instead of 8251s for serial communication, for example) were intentional. OK, there I go showing off :-) Just in case people think I'm still the fourteen year old weenie in the "face" archive and get shocked when I pitch up in Volos :-) ++L