x86/platform, acpi: Bypass legacy PIC and PIT in ACPI hardware reduced mode
authorLi, Aubrey <aubrey.li@linux.intel.com>
Wed, 11 Mar 2015 08:09:00 +0000 (16:09 +0800)
committerIngo Molnar <mingo@kernel.org>
Thu, 12 Mar 2015 11:07:13 +0000 (12:07 +0100)
commit7486341a98f26857f383aec88ffa10950087c3a1
tree8b21ca05646e33ad9853e223c1b3fbaf5b17b790
parent394838c96013ba414a24ffe7a2a593a9154daadf
x86/platform, acpi: Bypass legacy PIC and PIT in ACPI hardware reduced mode

On a platform in ACPI Hardware-reduced mode, the legacy PIC and
PIT may not be initialized even though they may be present in
silicon. Touching these legacy components causes unexpected
results on the system.

On the Bay Trail-T(ASUS-T100) platform, touching these legacy
components blocks platform hardware low idle power state(S0ix)
during system suspend. So we should bypass them in ACPI hardware
reduced mode.

Suggested-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Li Aubrey <aubrey.li@linux.intel.com>
Cc: <alan@linux.intel.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/54FFF81C.20703@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/acpi/boot.c