From: Al Stone al.stone@linaro.org
This series of patches starts with Hanjun's patch to create a kernel config item for CONFIG_ACPI_REDUCED_HARDWARE [0]. Building on that, I then reviewed all of the code that touched any of several fields in the FADT that the OSPM is supposed to ignore when ACPI is in Hardware Reduced mode [1]. Any time there was a use of one of the fields to be ignored, I evaluated whether or not the code was implementing Hardware Reduced mode correctly. Similarly, for each the flags in the FADT flags field that are to be ignored in Hardware Reduced mode, the kernel code was again scanned for proper usage. The remainder of the patches are to fix all of the situations I could find where the kernel would not behave correctly in this ACPI mode.
These seem to work just fine on the RTSM model for ARMv7, both with and without ACPI enabled, and with and without ACPI_REDUCED_HARDWARE enabled; similarly for the FVP model for ARMv8. The patches for ACPI on ARM hardware will be coming later but they presume that reduced HW mode is functioning correctly. In the meantime, there's no way I can think of to test all possible scenarios so feedback would be greatly appreciated.
[0] List at https://wiki.linaro.org/LEG/Engineering/Kernel/ACPI/AcpiReducedHw#Section_5:... [1] Please see the ACPI Specification v5.0 for details on Hardware Reduced mode.
Changes for v2: -- Remove patch that was outside of reduced HW mode changes -- Simplify CONFIG_ACPI_REDUCED_HARDWARE in Kconfig -- Simplify use of CONFIG_ACPI_REDUCED_HARDWARE in #ifdefs -- Ensure changelogs are present -- Combine and simplify previous patches 8 & 10
Al Stone (6): ACPI: introduce CONFIG_ACPI_REDUCED_HARDWARE to enable this ACPI mode ACPI: bus master reload not supported in reduced HW mode ACPI: HW reduced mode does not allow use of the FADT sci_interrupt field ACPI: ARM: exclude DMI calls ACPI: do not reserve memory regions for some FADT entries in HW reduced mode ACPI: in HW reduced mode, using FADT PM information is not allowed.
drivers/acpi/Kconfig | 8 ++++++++ drivers/acpi/bus.c | 3 ++- drivers/acpi/osl.c | 24 ++++++++++++------------ drivers/acpi/pci_link.c | 2 ++ drivers/acpi/processor_idle.c | 16 ++++++++++++++-- include/acpi/platform/aclinux.h | 4 ++++ include/linux/dmi.h | 2 +- 7 files changed, 43 insertions(+), 16 deletions(-)