* Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote: > On Sunday 11 October 2009 03:17:16 pm Yinghai Lu wrote: > > for > > > > http://bugzilla.kernel.org/show_bug.cgi?id=13940 > > > > some system when acpi are enabled, acpi clears some BAR for some devices without > > reason, and kernel will need to allocate devices for them. > > "ACPI clears some BARs"? I'm dubious. The handoff state is the same > whether we boot with "acpi=off" or not, so the BIOS can't be clearing > them. I really don't think the ACPI code in Linux clears BARs. The > Linux PCI code might be clearing BARs, but it sure would be nice to > know exactly why. Did you ever figure that out? > > > try to increase alignment to get more safe range for unassigned devices. > > > > Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> > > > > --- > > arch/x86/kernel/e820.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > Index: linux-2.6/arch/x86/kernel/e820.c > > =================================================================== > > --- linux-2.6.orig/arch/x86/kernel/e820.c > > +++ linux-2.6/arch/x86/kernel/e820.c > > @@ -1378,8 +1378,8 @@ static unsigned long ram_alignment(resou > > if (mb < 16) > > return 1024*1024; > > > > - /* To 32MB for anything above that */ > > - return 32*1024*1024; > > + /* To 64MB for anything above that */ > > + return 64*1024*1024; > > How do we know 64MB is the correct alignment? > > This feels like a hack that accidentally covers up the problem. I > don't think we understand what's happening well enough. Perhaps hidden chipset BARs getting protected by the larger granularity? Do we know the before/after allocation layout? Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
