On Fri, Oct 13, 2006 at 06:09:09PM +0100, Alan Cox wrote: > Ar Gwe, 2006-10-13 am 12:34 -0400, ysgrifennodd Adam Belay: > > I agree this needs to be fixed. However, as I previously mentioned, > > this isn't the right place to attack the problem. Remember, this wasn't > > originally a kernel regression. Rather it's a workaround for a known > > It's a kernel regression. It used to be reliable to read X resource > addresses at any time. No it didn't. It's undefined behaviour to perform *any* PCI config access to the device while it's doing a D-state transition. It may have happened to work with the chips you tried it with, but more likely you never hit that window because X simply didn't try to do that. > > Finally, it's worth noting that this issue is really a corner-case, and > > in most systems it's extremely rare that even incorrect userspace apps > > would have any issue. > > Except just occasionally and randomly in the field, probably almost > undebuggable and irreproducable - the very worst conceivable kind of > bug. Indeed. Only now we have software producing it, rather than hardware producing it. That's actually an improvement I think, since it forces awareness of the issue.
