🚀 go-pugleaf

David Syratt (syratt@midcoast.com.au) wrote:
: I am tying to install Linux using a 53c810 PCI Scsi adaptor (which works
: fine in DOS)

: When I try to install using Slackware/Redhat etc, I get the following
: message from the boot information screen.

: SCSI NCR 53c810 at memory 0xf4000000, io 0x6000, irq 0

: scsi0 : IRQ0 not free, detatching.

The SCSI-HOWTO says that common problem number 6 is:
----------------
6. If you encounter the message 
      "scsi%d: IRQ0 not free, detaching"
   or
      "scsi%d: IRQ255 not free, detaching"

   The NCR chip had all 0 or 1 bits stored in the PCI configuration 
   register.  Either you have configuration problems (see Common 
   Problem 1), or you have a defective mainboard BIOS.
----------------

and common problem 1:
----------------
1. Many people have encountered problems where the chip worked
   fine under DOS, but failed under Linux with a timeout on
   test 1 due to a lost interrupt.

   This is often due to a mismatch between the IRQ hardware
   jumper for a slot or mainboard device and the value set
   in the CMOS setup.  DOUBLE CHECK 
      - The IRQ you are using is used only by your onboard
        NCR chip, 
        or the slot an NCR board is installed in
      - Any main board jumpers selecting the IRQ for the
        onboard
        chip or slot match your CMOS setup.a
      - Some PCI mainboards have an "auto" assignment 
        feature, which will not work.

   It may also be due to PCI INTB, INTC, or INTD being selected
   on a PCI board in a system which only supports PCI INTA.  If you
   are using an NCR board which has jumpers to select between PCI 
   interrupt lines, make sure you are using INTA.

   Finally, PCI should be using level-sensitive rather
   than edge triggered interrupts.  Check that your board
   is jumpered for level-sensitive, and if that fails
   try edge-triggered because your system may be 
   broken.

   This problem is especially common with Viglen some Viglen
   motherboards, where the mainboard IRQ jumper settings are
   NOT as documented in the manual.  I've been told that what
   claims to be IRQ5 is really IRQ9, your mileage will vary.
----------------

Hope this helps,
-- 
Geoffrey D. Bennett (geoffrey@netcraft.com.au)
Computer Systems Manager, NetCraft Australia
http://www.netcraft.com.au/geoffrey/
Red Hat Linux Resellers: http://www.netcraft.com.au/redhat/