Messages in this thread |  | | | Date | Mon, 30 Aug 2004 10:02:32 -0400 (EDT) | | From | "Richard B. Johnson" <> | | Subject | Celistica with AMD chip-set |
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Hello all,
The Celistica server with the AMD chip-set has very poor PCI performance with Linux (and probably W$ too).
The problem was traced to incorrect bridge configuration in the HyperTransport(tm) chips that connect up pairs of slots.
I don't know how to make a generic chip-set bug-fix, and probably a new BIOS will come out with the correct values in the registers. But right now, the following initialization code will fix the box.
//-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= // // Some kind of problem, here. If the HyperTransport(tm) bridge // is found, one of the register values needs to be changed to // fix the bus performance. Need to turn back on prefetch. //
while((pdev = pci_find_device(0x1022, 0x7450, pdev)) != NULL) pci_write_config_dword(pdev, 0x4c, 0x2ec1);
Cheers, Dick Johnson Penguin : Linux version 2.4.26 on an i686 machine (5570.56 BogoMips). "DMA used to run at 180 Mb/s. With the new hardware it's only 30 Mb/s. Must be a software problem......." -actual complaint. Note 96.31% of all statistics are fiction.
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