Re: [Qemu-devel] [PATCH] ACPI: Add IRQ resource to HPET._CRS on Mac OS X

["Gabriel L. Somlo" <gsomlo@gmail.com>]

On Tue, Jan 21, 2014 at 08:38:51PM +0200, Michael S. Tsirkin wrote:
> On Tue, Jan 21, 2014 at 01:11:01PM -0500, Gabriel L. Somlo wrote:
> > Apple hardware invariably adds "IRQNoFlags() {0, 8}" to HPET._CRS,
> > and, at least on piix+smp, an OS X guest will panic unless IRQNoFlags
> > is present. On the other hand, Windows XP bluescreens whenever
> > IRQNoFlags is present. This patch conditionally includes IRQNoFlags
> > only when detecting the presence of an AppleSMC (as a heuristic
> > predictor for running a Mac OS X guest). Querying _OS and/or _OSI
> > directly was considered and rejected because such queries MAY NOT
> > be stateless from the OSPM standpoint, leading to potentially
> > unpredictable behavior.
> > 
> > Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> 
> Fine with me.
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> 
> I'll pick this up if no one complains.

In the mean time I updated the bootloader I was using (chameleon) to
the latest svn (2345), and was able to bring up Lion in addition to
SnowLeopard.

On Lion, without this patch (i.e. without IRQNoFlags on the HPET), all
four combinations (piix vs q35) X (up vs. smp) work fine.

I'd like to hold off on having this applied for now, until I get a
chance to figure out whether it matters moving forward (MountainLion,
Mavericks, etc). I'm not sure it's worth polluting the HPET DSDT node
with the "(LEqual(\_SB.PCI0.ISA.SMC._STA, 0x0B))" hack, only to
support (piix + smp) on an old version of OS X.

I'll follow up if anything new and interesting happens, but please
ignore it it for now...

Thanks,
--Gabriel