Messages in this thread |  | | Date | Sat, 15 Sep 2001 19:02:37 +0100 | From | Jonathan Morton <> | Subject | Re: Athlon: Try this (was: Re: Athlon bug stomping #2) |
| |
> > > +static void __init pci_fixup_athlon_bug(struct pci_dev *d) >> > +{ >> > + u8 v; >> > + pci_read_config_byte(d, 0x55, &v); >> > + if(v & 0x80) { >> > + printk(KERN_NOTICE "Stomping on Athlon bug.\n"); >> > + v &= 0x7f; /* clear bit 55.7 */ >> > + pci_write_config_byte(d, 0x55, v); >> > + } >> > +} >> > >> > Well, these are cosmetic changes anyway... >> > What is more important now: >> > 1) Do we have people who still see Athlon bug with the patch? >> > 2) Do Alan read these messages? ;-) >> >> Im watching the discussion with interest. If it proves to be the magic >> bullet I will ask VIA for guidance on the issue > >Not being a developer or guru on the internal software workings of the >hardware here, I have to ask, does this clear up some bug, or does it >disable the optimizations causing the problem? Is this a *fix* or a >band-aid?
AFAICT, it's a *fix*. The register in question is "for debug use only, never write anything other than zero in it" but generally shows non-zero when a faulty BIOS is installed. We're zeroing the bit that appears to cause the problem. It's highly unlikely to be an extra optimisation - if it is, it's an unsafe one.
-- -------------------------------------------------------------- from: Jonathan "Chromatix" Morton mail: chromi@cyberspace.org (not for attachments) website: http://www.chromatix.uklinux.net/vnc/ geekcode: GCS$/E dpu(!) s:- a20 C+++ UL++ P L+++ E W+ N- o? K? w--- O-- M++$ V? PS PE- Y+ PGP++ t- 5- X- R !tv b++ DI+++ D G e+ h+ r++ y+(*) tagline: The key to knowledge is not to rely on people to teach you it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |