Messages in this thread | | | Subject | Re: [PATCH] Use x2apic_supported() in the default_apic_id_valid() function. | From | Suresh Siddha <> | Date | Thu, 15 Mar 2012 14:21:44 -0700 |
| |
On Thu, 2012-03-15 at 13:23 -0700, Yinghai Lu wrote: > On Thu, Mar 15, 2012 at 11:03 AM, Steffen Persvold <sp@numascale.com> wrote: > > Use x2apic_supported() in the default_apic_id_valid() function. If x2apic mode is disabled (via nox2apic for example), x2apic_supported() will return false. > > > > This allows us to substitute the check in arch/x86/kernel/acpi/boot.c::acpi_parse_x2apic and avoid feigning the x2apic cpu feature in the NumaChip apic code. > > > > Signed-off-by: Steffen Persvold <sp@numascale.com> > > Reviewed-by: Daniel J Blueman <daniel@numascale-asia.com> > > I double checked on system with x2apic preenabled, > nox2apic in boot command line still works well and it > skips starting APs with apic id > 255. > > Acked-by: Yinghai Lu <yinghai@kernel.org>
This breaks the smpboot check if enabling interrupt-remapping/x2apic fails on a platform. We will be in xapic mode and we don't clear the x2apic cpufeature bit in this case and as such smpboot check will fail.
So this change breaks the commit c284b42abadbb22083bfde24d308899c08d44ffa.
I think the right thing is to have two different apid_id_valid checks one for xapic driver (apic_flat_64.c) and another for x2apic driver (x2apic_phys/cluster.c) and that way, x2apic MADT entries will be parsed only if bios has handed over the OS in x2apic mode or if we have selected the numachip model.
thanks, suresh
| |