RE: FW: slot number in Desk-top

["O'Shea, David J" <david.j.oshea@intel.com>]

Randy,

The question was whether Linux makes the "slot tags" available from
those tables.   (Assumed that they had to be processing the IRQ information
itself using either 9x table or MPS table.)  But those same tables also
make available slot labling information.  (Its just string data, for instance
"slot 1" or "U23" or whatever the vendor decided.

-David O'Shea

-----Original Message-----
From: Randy.Dunlap [mailto:rddunlap@osdl.org]
Sent: Wednesday, January 08, 2003 8:58 AM
To: O'Shea, David J
Cc: pci-sig@znyx.com
Subject: Re: FW: slot number in Desk-top


On Wed, 8 Jan 2003, O'Shea, David J wrote:

| Dinesh,
|
| The BIOS makes the information available to OS in at least
| two ways.  The first is the Windows9x PCI IRQ information tables,
| which also have PCI device to slot label information.  The table
| is so named because Microsoft defind it for Win9x, but many OS
| seem to make use of the table.    The second manner that this
| information is provided is via the ACPI tables.
|
| Current Linux and Solaris definitely do not support ACPI information
| retrieval into the OS.  (I do not know if they gather the Win9x PCI
| IRQ table information in either the OS, the bootloader, of via a
| application level program reading /dev/mem.   The Win9x table is
| memory mapped by the BIOS, and has a signature.)

Linux has used the PCI IRQ routing table (called PIRQ in Linux) for
years.  Linux reads this table very early during the boot process
and sets up interrupt vectors based on it.

Linux only uses the PIRQ table for uniprocessor (x86) systems.
For SMP (still x86), Linux 2.4 and earlier use the MP table for
interrupt routing info, unless the ACPI code in Linux 2.4 is being
used.

Linux 2.5 (development version) has these same options (PIRQ table,
MP table if not using ACPI, or use ACPI).  However, like David says,
ACPI for Linux is still very much under development, but it's making
much progress.

And ACPI is required for Linux on IA-64 of course.

Linux drivers don't read the PIRQ table directly.  They just request
that their interrupt handler be associated with a device (or function),
and then that device's associated interrupt line is tied to the
driver's interrupt handler.


| Perhaps one of the Linux gurus out there can tell us if the Win9x
| tables are read during OS startup somehow, and then made available
| to drivers.   And then in turn whether their is a Linux application
| that somehow makes use of this information via IOCTL, or one which
| simply reads /dev/mem.   I am sure that today the ACPI information
| is not yet used in Linux, that work is in development now for the
| next new kernal- so it will be a while longer yet before applications
| could be using ACPI information to solve the "what slot" riddle....
|
| -David O'Shea
|
|
| -----Original Message-----
| From: Dinesh Kumar [mailto:eyesol@rediffmail.com]
| Sent: Wednesday, January 08, 2003 12:46 AM
| To: pci-sig@znyx.com
| Subject: slot number in Desk-top
|
|
| Hi Experts,
|
| I have a basic qry.
| In a desk-top environment, is there a mechanism to find out which
| PCI card/resource is plugged in to which slot ? In other words, is
| it possible in OS level  to read slot number of a particular PCI
| card plugged in to a desk-top ?  Assume the machine is running in
| Solaris/Linux.
| Any one experienced similar problems ?
|
| Thanks in advance
|
| Dinesh

(not pretending to be a Linux guru)
(wishing PCI specs weren't so costly to individuals :(
-- 
~Randy