On 05/14/2010 04:28 PM, Jesse Barnes wrote: > On Fri, 14 May 2010 16:20:45 -0700 > "H. Peter Anvin" <hpa@xxxxxxxxx> wrote: > >> On 05/14/2010 03:47 PM, Jesse Barnes wrote: >>> >>> Wow and they're using cards that want to use I/O space? Funky. It's >>> too late to get this into 2.6.34, but that can't be what you were >>> expecting... I don't see a problem with getting something like this in >>> for 2.6.35. >>> >> >> Most cards on the market provide I/O BARs as a convenience to legacy >> BIOSes; they don't need the I/O BAR functionality from inside a >> full-featured OS. There are a few, key, exceptions, mainly in the form >> of legacy-interface devices like UARTs and VGA (note that VGA has its >> own routing bits and is therefore unaffected by this problem.) > > Yeah, it's the "legacy" part that I'm questioning. I'm just lamenting > that it's dying off so slowly... > > And yes, VGA is an unfortunate standard. > I'm not lamenting that fact, because my experience is that what ends up replacing it is often far worse. Consider UARTs -- no MMU dependencies at all, can be accessed with four lines of assembly, and compare it to EHCI debug port, the driver for which is over 900 lines in the Linux kernel -- and that assumes that you're already in flat mode. -hpa -- 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
