My videocard is at pci bus 3:14:0, but the scan ends at 3:2:0. This leads to the comment: 
(II) Primary Device is: ISA
(EE) No devices detected

I'm running Fedora Core 6 (Zod) on Dell PowerEdge 750.

-- snip Xorg.0.log --
X Window System Version 7.1.1
Release Date: 12 May 2006
X Protocol Version 11, Revision 0, Release 7.1.1
Build Operating System: Linux 2.6.9-34.ELsmp i686 Red Hat, Inc.
..
(II) Loading /usr/lib/xorg/modules/libpcidata.so
(II) Module pcidata: vendor="X.Org Foundation"
        compiled for 7.1.1, module version = 1.0.0
        ABI class: X.Org Video Driver, version 1.0
(--) using VT number 7
(II) PCI: PCI scan (all values are in hex)
(II) PCI: 00:00:0: chip 8086,2578 card 0000,0000 rev 02 class 06,00,00 hdr 00
(II) PCI: 00:03:0: chip 8086,257b card 0000,0000 rev 02 class 06,04,00 hdr 01
(II) PCI: 00:06:0: chip 8086,257e card 0000,0000 rev 02 class 08,80,00 hdr 00
(II) PCI: 00:1c:0: chip 8086,25ae card 0000,0000 rev 02 class 06,04,00 hdr 01
(II) PCI: 00:1d:0: chip 8086,25a9 card 1028,0165 rev 02 class 0c,03,00 hdr 80
(II) PCI: 00:1d:1: chip 8086,25aa card 1028,0165 rev 02 class 0c,03,00 hdr 00
(II) PCI: 00:1d:4: chip 8086,25ab card 1028,0165 rev 02 class 08,80,00 hdr 00
(II) PCI: 00:1d:5: chip 8086,25ac card 1028,0165 rev 02 class 08,00,20 hdr 00
(II) PCI: 00:1d:7: chip 8086,25ad card 1028,0165 rev 02 class 0c,03,20 hdr 00
(II) PCI: 00:1e:0: chip 8086,244e card 0000,0000 rev 0a class 06,04,00 hdr 01
(II) PCI: 00:1f:0: chip 8086,25a1 card 0000,0000 rev 02 class 06,01,00 hdr 80
(II) PCI: 00:1f:2: chip 8086,25a3 card 1028,0165 rev 02 class 01,01,8a hdr 00
(II) PCI: 00:1f:3: chip 8086,25a4 card 1028,0165 rev 02 class 0c,05,00 hdr 00
(II) PCI: 01:01:0: chip 8086,1075 card 1028,0165 rev 00 class 02,00,00 hdr 00
(II) PCI: 02:01:0: chip 8086,1010 card 8086,1012 rev 01 class 02,00,00 hdr 80
(II) PCI: 02:01:1: chip 8086,1010 card 8086,1012 rev 01 class 02,00,00 hdr 80
(II) PCI: 03:02:0: chip 8086,1076 card 1028,0165 rev 00 class 02,00,00 hdr 00
(II) PCI: End of PCI scan
..
(II) Primary Device is: ISA
(EE) No devices detected.
-- snap --

-- snip lspci --
00:00.0 Host bridge: Intel Corporation 82875P/E7210 Memory Controller Hub (rev 02)
00:03.0 PCI bridge: Intel Corporation 82875P/E7210 Processor to PCI to CSA Bridge (rev 02)
00:1c.0 PCI bridge: Intel Corporation 6300ESB 64-bit PCI-X Bridge (rev 02)
00:1d.0 USB Controller: Intel Corporation 6300ESB USB Universal Host Controller (rev 02)
00:1d.1 USB Controller: Intel Corporation 6300ESB USB Universal Host Controller (rev 02)
00:1d.4 System peripheral: Intel Corporation 6300ESB Watchdog Timer (rev 02)
00:1d.5 PIC: Intel Corporation 6300ESB I/O Advanced Programmable Interrupt Controller (rev 02)
00:1d.7 USB Controller: Intel Corporation 6300ESB USB2 Enhanced Host Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 0a)
00:1f.0 ISA bridge: Intel Corporation 6300ESB LPC Interface Controller (rev 02)
00:1f.2 IDE interface: Intel Corporation 6300ESB SATA Storage Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 6300ESB SMBus Controller (rev 02)
01:01.0 Ethernet controller: Intel Corporation 82547GI Gigabit Ethernet Controller
02:01.0 Ethernet controller: Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) (rev 01)
02:01.1 Ethernet controller: Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) (rev 01)
03:02.0 Ethernet controller: Intel Corporation 82541GI Gigabit Ethernet Controller
03:0e.0 VGA compatible controller: ATI Technologies Inc Rage XL (rev 27)
-- snap --

With version 7.0.0 this doesn't appear on the same machine.
-- snip Xorg.0.log --
(II) Loading /usr/lib/xorg/modules/libpcidata.so
(II) Module pcidata: vendor="X.Org Foundation"
        compiled for 7.0.0, module version = 1.0.0
        ABI class: X.Org Video Driver, version 0.8
(++) using VT number 7
(II) PCI: PCI scan (all values are in hex)
(II) PCI: 00:00:0: chip 8086,2578 card 0000,0000 rev 02 class 06,00,00 hdr 00
(II) PCI: 00:03:0: chip 8086,257b card 0000,0000 rev 02 class 06,04,00 hdr 01
(II) PCI: 00:06:0: chip 8086,257e card 0000,0000 rev 02 class 08,80,00 hdr 00
(II) PCI: 00:1c:0: chip 8086,25ae card 0000,0000 rev 02 class 06,04,00 hdr 01
(II) PCI: 00:1d:0: chip 8086,25a9 card 1028,0165 rev 02 class 0c,03,00 hdr 80
(II) PCI: 00:1d:1: chip 8086,25aa card 1028,0165 rev 02 class 0c,03,00 hdr 00
(II) PCI: 00:1d:4: chip 8086,25ab card 1028,0165 rev 02 class 08,80,00 hdr 00
(II) PCI: 00:1d:5: chip 8086,25ac card 1028,0165 rev 02 class 08,00,20 hdr 00
(II) PCI: 00:1d:7: chip 8086,25ad card 1028,0165 rev 02 class 0c,03,20 hdr 00
(II) PCI: 00:1e:0: chip 8086,244e card 0000,0000 rev 0a class 06,04,00 hdr 01
(II) PCI: 00:1f:0: chip 8086,25a1 card 0000,0000 rev 02 class 06,01,00 hdr 80
(II) PCI: 00:1f:2: chip 8086,25a3 card 1028,0165 rev 02 class 01,01,8a hdr 00
(II) PCI: 00:1f:3: chip 8086,25a4 card 1028,0165 rev 02 class 0c,05,00 hdr 00
(II) PCI: 01:01:0: chip 8086,1075 card 1028,0165 rev 00 class 02,00,00 hdr 00
(II) PCI: 02:01:0: chip 8086,1010 card 8086,1012 rev 01 class 02,00,00 hdr 80
(II) PCI: 02:01:1: chip 8086,1010 card 8086,1012 rev 01 class 02,00,00 hdr 80
(II) PCI: 03:02:0: chip 8086,1076 card 1028,0165 rev 00 class 02,00,00 hdr 00
(II) PCI: 03:0e:0: chip 1002,4752 card 1028,0165 rev 27 class 03,00,00 hdr 00
(II) PCI: End of PCI scan
-- snap --