In mailing-lists.linux-kernel, you wrote:
> I suppose this question is stuff I can find elsewhere but: where do I find
> just that patch alone (so that I cen see about adapting it to my redhat
> kernel)
The relevant function is from arch/i386/kernel/pci-pc.c:
static void __init pci_fixup_via_athlon_bug(struct pci_dev *d)
{
u8 v;
pci_read_config_byte(d, 0x55, &v);
if (v & 0x80) {
printk("Trying to stomp on Athlon bug...\n");
v &= 0x7f; /* clear bit 55.7 */
pci_write_config_byte(d, 0x55, v);
}
}
Note also this line from struct pci_fixup pcibios_fixups[] in the same
file:
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8363_0, pci_fixup_via_athlon_bug },
I believe that all you have to do is add the above line to
pcibios_fixups[] and add the above function to pci-pc.c.
> and/or how do I do it from userspace ;) (i assume i just have to
> write to some registers or something using some user-space mechanism
> that i am unaware of???).
You can see what pci_fixup_via_athlon_bug does: it clears bit 7 of
register 0x55 of the PCI device VIA 8363. On a machine that has a VIA
8363 (the northbridge), I believe it will be PCI ID 0:0.0 (0th bus,
0th device, 0th subdevice). You can check this with 'lspci -n -s
0:0.0', it should say '00:00.0 Class 0600: 1106:0305' followed by a
revision (2 for the KT133, 3 for the KT133A)
Then as root, you do 'setpci -s 0:0.0 55' to query the register, do
the computation of clearing bit 7 of the result to get a value YY, and
do 'setpci -s 0:0.0 55=YY' to set the register. Note that both 55 and
YY are in hexadecimal.
Cheers, Wayne
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This archive was generated by hypermail 2b29 : Thu Nov 15 2001 - 21:00:26 EST