AW: Slot number in Desk-top - huh?

["Heiner, Andreas" <HeinerA@becker.de>]

Hello,

I would agree and disagree.

The physical position can be determined. The physical position depends on
the connection of the IDSEL-Signal and depends on the Motherboard. The
connection is not defined by the pci spec, so it is different from system to
system. The abstraction towards the operating system is done by low level
software (in PC architectures inside the pci bios, in other systems inside
the B(oard)S(upport)P(ackage).

If you have knowledge about the motherboard and system you use, you can use
the host pci bridge to activate one special IDSEL line and perform some
configuration reads. Now you can determine the physical position (e.g. the
slot information). For example the linux x-server does it in this way
(xfree86 configuration files contains physical positions).

Normally the IDSEL signals are connected to the AD-Lines 31 downto 16 (12?).
The order the devices and slots are connected is free. If you have no
knowledge about the system you can only check if the configuration is
unchanged. If you have the information about the internal connections (and
the programming of the host bridge) you can find out the physical position
(slot number, right slot, left slot or what ever you want).

Maybe this helps, unfortunately I'm responsible for Hardware, so I have no
example source for you.

Regards,

Andreas

-----Ursprüngliche Nachricht-----
Von: Mike Dini [mailto:mdini@dinigroup.com] 
Gesendet: Mittwoch, 8. Januar 2003 20:10
An: pci-sig@znyx.com
Betreff: Slot number in Desk-top - huh?

I'm confused as to how the original question deviated into the IRQ's, 
unless I misunderstood the original question.  I thought Dinesh asked the following question (paraphrasing):

    I have a board plug into PCI/PCIX/ et al.
    How does the driver determine the physical
    location of that board?

My private answer to him went as follows:

You can't.  This is a fundamental problem with PCI and it is a problem we have all the time.  On a PCI bus, you can figure what board is plugged in, but it is impossible to determine which physical slot the board is plugged into.  This is all PCI, not just Sun.  This can be quite troublesome if you 
put two of the same boards into a system and, for example, they get cabled differently to something external.

The only way to solve this is to put a DIP switch on the PWB or add some 
sort of an ID to the circuit.  Upon installation, the user (or other) must tell the driver which of these ID's in connected to which function.

Now I state again in clearer prose:  Across platforms, it is impossible in PCI to correctly determine the physical location of a PCI resource without some external intervention.

Agree/Disagree?

>|
>| 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


*******************************************
Diese E-Mail enthaelt vertrauliche und/oder rechtlich geschuetzte Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail irrtuemlich erhalten haben, informieren Sie bitte sofort den Absender und loeschen Sie diese Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe dieser Mail ist nicht gestattet.
 
This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the contents in this e-mail is strictly forbidden.
*******************************************