PCI spec question/possible VIA quirk?

f.duncan.m.haldane@worldnet.att.net
Sun, 12 Aug 2001 20:54:06 -0400 (EDT)


Hi,

Can anyone tell me what the PCI specs say config registers 0x2c:0x2f
should contain?

------------------------lspci -x says:------------------------------
00:01.0 PCI bridge: VIA Technologies, Inc. VT8363/8365 [KT133/KM133 AGP]
00: 06 11 05 83 07 00 30 22 00 00 04 06 00 00 01 00
10: 00 00 00 00 00 00 00 00 00 01 01 00 f0 00 00 00
20: 00 f6 f0 f7 00 fc f0 fd 00 00 00 00 43 10 2f 80 <====== Here!
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0c 00
---------------------------------------------------------------------

In drivers/pci/pci.c (all 2.4.x kernels) pci_read_bridge_bases()
is reading "mem_limit_hi" from them.
(PCI_PREF_LIMIT_UPPER32 = 0x2c in pci.h)

This seems to need to be 00 00 00 00 for the pci setup to work
properly. A non-zero value leads to the error:

"PCI: Unable to handle 64-bit address space for %s\n"

(Hacking in a line that resets mem_limit_hi to 0 seems to make
everything work fine; without it the AGP card doesnt get set up
correctly for accelerated modes)

Are the strange values in these registers maybe a VIA quirk?
(most of the pci devices have such values.)

Any suggestions would be appreciated!

Duncan Haldane
(please cc: any reply to me)

----------------------------------
E-Mail: f.duncan.m.haldane@worldnet.att.net
Date: 12-Aug-2001
Time: 20:46:29

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