mbox series

[v2,0/2] Prefer using _OSC method over deprecated _PDC

Message ID 20230516150558.149886-1-michal.wilczynski@intel.com
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Series Prefer using _OSC method over deprecated _PDC | expand

Message

Michal Wilczynski May 16, 2023, 3:05 p.m. UTC 
ACPI 3.0 introduced a new Operating System Capabilities _OSC control
method. This method is similar to _PDC, which was marked as deprecated
in ACPI 3.0.

Prefer using _OSC method over deprecated _PDC in the acpi_bus_init(). In
case of the failure of the _OSC, try using _PDC as a fallback.

Testing done:
Tested on physical server with BIOS implementing _OSC methods. In this
case acpi_processor_osc() was executed for each CPU core. acpi_run_osc()
returned success indicating that _OSC method succeeded.

Tested on qemu VM to check whether the code would work on a SeaBios (the
default for qemu, doesn't support _OSC methods, or _PDC). This way I was
able to see how code behaves in case BIOS doesn't implement _OSC. In
that case the function
acpi_run_osc() returned failure, which propagated all the way up to
acpi_early_processor_osc(). The logic reponsible for triggering _PDC
execution was triggered correctly.

Tested this using debug messages with printk.

v2:
 - fixed compilation issues on ia64 and arm

Michal Wilczynski (2):
  acpi: Use _OSC method to convey processor OSPM capabilities
  acpi: Move logic responsible for conveying processor OSPM capabilities

 arch/ia64/include/asm/acpi.h  |   4 +-
 arch/x86/include/asm/acpi.h   |  12 ++--
 drivers/acpi/acpi_processor.c | 130 ++++++++++++++++++++++++++++------
 drivers/acpi/bus.c            |  11 +--
 drivers/acpi/internal.h       |   7 +-
 drivers/acpi/processor_pdc.c  |  82 +--------------------
 include/acpi/pdc_intel.h      |   1 +
 include/acpi/processor.h      |   2 +-
 8 files changed, 133 insertions(+), 116 deletions(-)