Date: Mon, 10 Apr 2006 14:10:42 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: bms@spc.org Cc: mwm-keyword-freebsdhackers.102a7e@mired.org, scottl@samsco.org, ceri@submonkey.net, hackers@FreeBSD.org Subject: Re: Using any network interface whatsoever Message-ID: <20060410.141042.25162164.imp@bsdimp.com> In-Reply-To: <20060410194746.GY80492@spc.org> References: <20060409090757.GW80492@spc.org> <20060409.184825.99254285.imp@bsdimp.com> <20060410194746.GY80492@spc.org>
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In message: <20060410194746.GY80492@spc.org>
Bruce M Simpson <bms@spc.org> writes:
: On Sun, Apr 09, 2006 at 06:48:25PM -0600, M. Warner Losh wrote:
: > I though thtis was already supported. We export bus/slot/function
: > information devd, which can be used to configure the device.
:
: If I've read the specs or code incorrectly please do let me know --
: my reading here is based on the PCI code as I understand it to be.
:
: As I understand things, the bus/slot/function numbers in pci(9), the
: *slot* number isn't guaranteed to have any meaning in geographic reality;
: it's purely what the PCI logic thinks the bus topology looks like and
: hence what the device numbers are. See BUGS in pci(9).
The device number is fixed for a given mother board slot. It will
never change unless you change the mother board.
However, for stacking topologies the slot is the position in the stack.
: It won't tell you that a given card is in a given slot with any degree
: of certainty or consistency across the range of backplanes available
: from multiple vendors -- although people may like to give PICMG a try
: as I hear such boards are consistent about such things.
Correct.
: In the old Microsoft-specified $PIR tables there was a column which
: allowed you to map the bus/device/function tuple we use to a physical
: slot number, but this only ran 1-6. With multiple PCI buses and slot
: types, as well as multifunction devices, this information quickly became
: unusable and unreliable, although src/tools/tools/pirtool will happily
: display this information.
Correct.
: ACPI as you no doubt know does away with the $PIR tables, although many
: BIOS still export them to allow legacy DOS programs which use PCI to work.
: There is an extension to ACPI which adds geographical slot addressing
: to the device tree but I haven't seen any systems which support it.
OK. Physical slot information.
Warner
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