On Thu, 5 Feb 2009, Benjamin Herrenschmidt wrote: > On Wed, 2009-02-04 at 11:24 +0100, Rafael J. Wysocki wrote: > > This message has been generated automatically as a part of a report > > of recent regressions. > > > > The following bug entry is on the current list of known regressions > > from 2.6.28. Please verify if it still should be listed and let me know > > (either way). > > I still don't know what's the best way to handle that one... the bug is > in X and I don't see a way to work around it without removing support > for legacy memory access from the kernel :-( Or doing it in a way that > doesn't allow userspace to differenciate between the kernel not > supporting it vs. the HW not supporting it, causing X to fallback to > even more broken crap. Is it a really a bug in X, or a misunderstanding between X and the kernel as to what existence of the legacy_mem file implies? I may have got this quite wrong, but to me it appears that X assumes that existence of the legacy_mem file implies that it will be useful; whereas the kernel thinks it can make the legacy_mem file available, even if it cannot be used for mmapping mem - which is its sole purpose? What if pci_create_legacy_files() were to call some new verification routine, and only create the legacy_mem file if it would be usable? (But perhaps that cannot be known at the time it needs to be created.) Hugh > > I'll try to find out the extent of the X problem and whether that's > fixable in a way that can hit distros. > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12608 > > Subject : 2.6.29-rc powerpc G5 Xorg legacy_mem regression > > Submitter : Hugh Dickins <hugh@xxxxxxxxxxx> > > Date : 2009-01-21 21:12 (15 days old) > > First-Bad-Commit: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d3a54014e2a94bd37b7dee5e76e03f7bc4fab49a > > References : http://marc.info/?l=linux-kernel&m=123257250431870&w=4 > > Handled-By : Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
