I have a Tyan S1867 (Server Set III HE) for which I'd like to have AGP
support. Here's the relevant output of lspci -v :
00:00.0 Host bridge: ServerWorks CNB20HE (rev 22)
Flags: fast devsel
Memory at fa000000 (32-bit, prefetchable) [disabled] [size=32M]
Memory at feafb000 (32-bit, non-prefetchable) [disabled] [size=4K]
00:00.1 PCI bridge: ServerWorks CNB20HE (rev 01) (prog-if 00 [Normal decode])
Flags: bus master, 66Mhz, medium devsel, latency 64
Bus: primary=00, secondary=01, subordinate=01, sec-latency=64
Memory behind bridge: fd000000-fdffffff
Prefetchable memory behind bridge: f0000000-f7ffffff
Capabilities: [80] AGP version 2.0
...
...
...
01:00.0 VGA compatible controller: nVidia Corporation NV15 Bladerunner
(Geforce2 GTS) (rev a4) (prog-if 00 [VGA])
Subsystem: Elsa AG: Unknown device 0c56
Flags: bus master, 66Mhz, medium devsel, latency 248, IRQ 17
Memory at fd000000 (32-bit, non-prefetchable) [size=16M]
Memory at f0000000 (32-bit, prefetchable) [size=128M]
Expansion ROM at <unassigned> [disabled] [size=64K]
Capabilities: [60] Power Management version 1
Capabilities: [44] AGP version 2.0
The first thing to be noted is that the Capabilities Pointer for this chipset
is on the AGP bridge not on the Host bridge like it is for currently
supported chips. If I change the line
if ((dev = pci_find_class(PCI_CLASS_BRIDGE_HOST << 8, NULL)) == NULL)
to
if ((dev = pci_find_class(PCI_CLASS_BRIDGE_PCI << 8, NULL)) == NULL)
in the agp_find_supported_device routine then I am able to load the patched
agpgart module. But, unfortunately, it is clear that the intel_generic setup
routines won't work. Eg, intel_fetch_size returns 256 MB no matter what I
have the aperture set to in the BIOS.
Just poking around I notice that the byte at 0x8c changes from
1,3,5,7,9,11,13 as I change the aperture to 32,64,128,.256,512,1G,2G.
Does anyone have the relevant documentation for the ServerWorks AGP
configuration registers?
Thanks,
Marvin