[GRLUG] PCI VGA Help

[Adam Tauno Williams]

On Wed, 2011-04-20 at 10:06 -0400, Michael Mol wrote:
> On Wed, Apr 20, 2011 at 9:14 AM, Adam Tauno Williams
> <awilliam at whitemice.org> wrote:
> > On Wed, 2011-04-20 at 07:54 -0500, L. V. Lammert wrote:
> >> On Wed, 20 Apr 2011, Adam Tauno Williams wrote:
> >> > On Tue, 2011-04-19 at 11:44 -0500, L. V. Lammert wrote:
> >> > > Need someone with knowledge of hw - we have a passive backplane system
> >> > > with ISA & PCI where we need a 2nd monitor (Ubuntu 10.04)
> >> > Can you be more precise about "have a passive backplane system"?
> >> In what way? 10 ISA + 6 PCI? Two slots are ISA/PCI for the CPU and a
> >> spare.
> > Is this some type of vertical appliance or a backplane extension to a
> > "PC".  How does the backplane attach to the mainboard [simple PCI ribbon
> > cable to the planar?  Or does the host motherboard have provisions for
> > the attachment of the backplane?].
> If it's the kind of system I had as a desktop box for several years,
> here's how it would be laid out:
> * You have a CPU card which has northbridge, southbridge, CPU, I/O,
> etc on it. Will have headers for serial, USB, etc. May have onboard
> network and video, but all of this on the CPU card.

Yep, I've seen those.  I've also seen tethered backplanes.

> * You have a "motherboard" in a 4U case which has three PCI-PCI
> bridges on it and possibly some routing logic for a keyboard
> connector.

Right, which makes the "passive backplane" a bit of a lie; that is just
an inherited/colloquial term.  There is nothing "passive" about a PCI
bus - PCI does device capability and resource negotiation and
'understands' bus-to-bus data transfer.  The PCI bus controllers are a
significant factor in getting something like multiple video cards spread
over multiple busses to actually work.  If you can't access them, or at
least interogate them to some degree, you might very well be 'screwed'.

> The backplane will have several PCI slots in it. The "ISA" slot is
> actually a CPU-board-only connection using an ISA edge connector
> socket, and how the CPU board accesses what little services the
> backplane offers. (My system offered a fan header, something for
> chassis intrusion detection, and I think some kind of sysadmin bus
> like smbus, but I don't recall exactly)
> In my system, I was able to run PCI 2.1 devices, at least. I may have
> been able to run PCI 2.2, but I don't know for certain. (And, of
> course, he may not be running the same exact hardware)
> > You have [probably] at least three PCI busses in this case. All all the
> > PCI slots 'narrow' or do some/all of them have extensions [there are a
> > duzzying number of PCI versions at this point].
> > Again, what options related to the PCI bus appear in the host BIOS?  Is
> > the current video card built-in or on the bus?  If on the bus is it on
> > the backplane or in a slot on the host's motherboard?


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