From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <20031103141125.10229.qmail@kunk.qbjnet.com> Subject: Re: IRQS on 6 Slot Macs In-Reply-To: <1067842481.17970.8.camel@gaston> To: Benjamin Herrenschmidt Date: Mon, 3 Nov 2003 08:11:25 -0600 (CST) From: Bob Brose Cc: Robert E Brose II , linuxppc-dev list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: User Benjamin Herrenschmidt says: > On Mon, 2003-11-03 at 14:35, Robert E Brose II wrote: > > > A couple of things right off, the rage128 appears to be the only thing on > > irq 23 however 23 doesn't show up in /proc/interrupts meaning, I suppose, > > that it's not using the interrupt. So why does the drm complain? > > > > How come everything from slots 3-6 says it's on the same interrupt (25)? > > I don't know what's up with the DRM not liking your interrupt. I can > answer for the sharing of USB, symbios and firewire interrupts: all 3 > slots share one interrupt because of bad motherboard design :) > Basicallly, what they did when designing that machine was to use a > standard powersurge design with 3 slots and replace one of them > with a PCI<->PCI bridge. Since they didn't "know" how to get more > interrupt lines out of Grand Central, they just also stuffed all > interrupt lines together for those 4 slots (I'm pretty sure GC do > have spare lines they could have used, but that would have meant > updating Open Firmware to understand the layout, I doubt the people > who designed that machine wanted to dive into that). > > Ben. I suppose then that I should reorder the cards so that the ones generating the most interrupts would be in the first 2 slots? It's pretty funny having the possibility of the use of lots of irqs then ending up with x86 style sharing. :( Bob -- /~\ The ASCII | Robert E. Brose II N0QBJ \ / Ribbon Campaign | http://www.qbjnet.com/ X Help cure | mailto:bob@qbjnet.com / \ HTML Email | public key at http://www.qbjnet.com/key.html ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/