Re: Subsystem IDs and their meaning

[Steve Kappes <steve@iphase.com>]

Number two is the most correct. If only one field was required,
there would be only one field. Personally I don't see any
reason to have required the subsystem field. A unique vendor and
device ID with a zero subsystem ID should have been enough
to indentify a device.

Dan Mick wrote:
> 
> Hi, all.  There seems to be a difference of opinion about the
> interpretation of the spec WRT Subsystem IDs.  I've asked Warren
> Questo at Intel to help clarify, but have gotten no response as yet.
> 
> Can I run a quick opinion poll?
> 
> How many of you think either of the below?  (I believe them to be
> mutually-exclusive, so you can't think both.):
> 
> 1) The Subsystem Vendor ID and Subsystem ID can be used, by
> themselves, as the only pieces of information to uniquely identify a
> given PCI device (i.e. 32 bits of config space is a
> unique-in-all-the-world identifier for "this device in this
> subsystem").
> 
> 2) The Subsystem Vendor ID and Subsystem ID can be used only in
> conjunction with the Vendor ID and Device ID to uniquely identify a
> given PCI device. (i.e. 64 bits of config space is a
> unique-in-all-the-world identifier for "this device in this
> subsystem".)
> 
> Raise your e-hands, please, 1 or 2 (privately or publicly, as you
> like, and I'll summarize, anonymously or otherwise, as you like).
> 
> ---
> 


-- 


Steve Kappes Interphase Corp. steve@iphase.com