From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264366AbTL3EB6 (ORCPT ); Mon, 29 Dec 2003 23:01:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264367AbTL3EB6 (ORCPT ); Mon, 29 Dec 2003 23:01:58 -0500 Received: from cpe-024-033-224-91.neo.rr.com ([24.33.224.91]:64644 "EHLO neo.rr.com") by vger.kernel.org with ESMTP id S264366AbTL3EBp (ORCPT ); Mon, 29 Dec 2003 23:01:45 -0500 Date: Mon, 29 Dec 2003 22:50:37 +0000 From: Adam Belay To: Amit Gurdasani Cc: linux-kernel@vger.kernel.org Subject: Re: EISA ID for PnP modem and resource allocation Message-ID: <20031229225037.GB3198@neo.rr.com> Mail-Followup-To: Adam Belay , Amit Gurdasani , linux-kernel@vger.kernel.org References: <20031229143711.GA3176@neo.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 30, 2003 at 03:59:16AM +0400, Amit Gurdasani wrote: > :Without special hardware modifications, it is usually unsafe to share irqs > :between isa devices. > > Ah. So 2.4's behavior was broken then? Perhaps in this case. > > :> The reason I ask is that I also have a jumpered SB16 on IRQ 5, and loading > :> the 8250 driver before the snd_sb16 driver results in the SB16's IRQ being > :> allocated for the modem, which prevents the SB16 driver from loading. > :> Loading the SB16 driver first results in resource starvation for the modem, > :> and the 8250 driver is only able to set up the onboard serial ports ttyS0 > :> and ttyS1. > : > :You may want to try changing the jumper on your SB16 to allow for PnP > :autoconfiguration. > > It's a pre-PnP SB16 from 1994, as far as I can tell -- IRQ, I/O port and DMA > channels can be set only by setting jumpers. I suppose I could pull the card > out and set its IRQ setting to something the modem won't claim. Because of detection limitations in legacy hardware, you may have to notify the Plug and Play Layer that your device is using irq 5. Booting with the parameter pnp_reserve_irq=5 will prevent resource conflicts with the legacy SB16 device. > > :> In the meantime, I'm using the isapnptools to set up the modem with IRQ 4 > :> before loading either driver. The result is that the SB16 driver gets IRQ 5 > :> as needed, and ttyS0 is set up with IRQ 0 (is this OK?), but I'd really like > :> to use the kernel ISA PnP support. > : > :Could I please see a copy of your /proc/interrupts. > > CPU0 > 0: 314288 XT-PIC timer > 1: 1024 XT-PIC i8042 > 2: 0 XT-PIC cascade > 5: 7444 XT-PIC SoundBlaster > 8: 1 XT-PIC rtc > 9: 4675 XT-PIC ide2 > 10: 41 XT-PIC eth0 > 11: 89930 XT-PIC i91u > 12: 10092 XT-PIC i8042 > 15: 57 XT-PIC ide1 > NMI: 0 > LOC: 0 > ERR: 0 > MIS: 0 > > Apart from these, dmesg output shows these IRQs allocated: > > ttyS0 at I/O 0x3f8 (irq = 0) is a 16550A > ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A > ttyS2 at I/O 0x3e8 (irq = 4) is a 16550A > parport0: irq 7 detected Hmm, it shouldn't be reporting irq 0. The probbing code may be confused. I would guess it is on irq 4. > > Additionally, pnpdump says the modem can only claim an IRQ line from among > 3, 4, 5, 7, 9, 10, 11, 12 or 15 in various configurations. It appears that you have an unresolvable resource conflict. I'm working on a more flexable resource manager for the 2.7 kernel. For now, I recommend that you disable one of your serial ports in your BIOS configuration interface and try booting with pnp_reserve_irq=5. Alternatively you could try enabling PnPBIOS support. There's a slight chance that the pci code will reroute ide2 to 14 (assuming ide2 is pci), leaving room for your modem on 9. You'll still need to reserve irq 5 as stated above. Thanks, Adam