On Tuesday, January 6, 2009 11:02 am Bjorn Helgaas wrote: > On Monday 05 January 2009 01:30:06 pm Michał Mirosław wrote: > > Some BIOSes hide 'overflow' device (dev #6) for i82875P/PE chipsets. > > The same happens for i82865P/PE. Add a quirk to enable this device. > > This allows i82875 EDAC driver to bind to chipset's dev #6 and not > > dev #0 as the latter is used by AGP driver. > > > > After testing this patch for couple of days on my laptop (i82856P) > > it looks like something is resetting device 0 (MCH) config register > > 0xF4 to zero and effectively disabling the device again. The delay > > looks random to me. > > The BIOS left the device hidden. When you enable it with the quirk, > the fact that it mysteriously gets disabled later seems like a pretty > clear indication that something else we don't know about is using the > device. Since there's no synchronization between the "something else" > and the i82875p_edac.c driver, it seems like you're introducing the > possibility for problems. > > I don't know anything about the EDAC driver. Is the value it provides > really worth the possible problems with this approach? Maybe it is, > but I don't want to be the one to debug a random interaction that > causes a problem. Yeah, there's some uncertainty there for sure so I've dropped the patch. If it really provides a compelling feature we can always add it again with a config option or runtime option to enable it. -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
