On Friday, January 10, 2014 03:52:14 PM al.stone@xxxxxxxxxx wrote: > From: Al Stone <al.stone@xxxxxxxxxx> > > 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 have been submitted elsewhere 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. Quite frankly, I'm seeing a pattern in this patchset that I'm not really liking, which is making changes on a hunch. Especially things like changing code under #ifdef CONFIG_X86 and similar. Can we please focus on making changes that are *known* to be necessary and where we know *why* this is the case? > [0] List at https://wiki.linaro.org/LEG/Engineering/Kernel/ACPI/AcpiReducedHw#Section_5:_ACPI_Software_Programming_Model > [1] Please see the ACPI Specification v5.0 for details on Hardware Reduced > mode (sections 3.11.1, 4.1, 5.2.9, at a minimum). > > Changes for v6: > -- Allow selection of CONFIG_ACPI_REDUCED_HARDWARE_ONLY to be more > architecture-independent, but make it harder to accidentally enable. > -- Make sure that ACPI ECs do not use the ACPI global lock when in > hardware reduced mode (I had missed this case in earlier reviews > of the kernel tree). > > Changes for v5: > -- Clarify that if the kernel config option to build ACPI hardware reduced > mode is used, it builds a hardware reduced *only* kernel (i.e., full > legacy ACPI mode will no longer work). > > Changes for v4: > -- Given the current state of ACPICA, disable CONFIG_ACPI_REDUCED_HARDWARE > for use on anything other than ARM. > -- Replaced #ifdefs with run-time checking for hardware reduced mode, > whenever possible > > Changes for v3: > -- Modified enabling ACPI_REDUCED_HARDWARE in ACPICA when using > kernel config item CONFIG_ACPI_REDUCED_HARDWARE; now consistent > with ACPICA code base where needed > -- Enable X86 for CONFIG_ACPI_REDUCED_HARDWARE > -- Minimize bus master reload patching > -- Remove unneeded patch for dmi_check_system() (was 4/6) > -- Correct the patch for removing unneeded map/unmap of FADT fields > > 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_ONLY to enforce 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: in HW reduced mode, using FADT PM information is not allowed. > ACPI: do not map/unmap memory regions for FADT entries in reduced HW > mode > ACPI: make sure ECs do not use the ACPI global lock > > drivers/acpi/Kconfig | 12 ++++++++++++ > drivers/acpi/bus.c | 30 ++++++++++++++++-------------- > drivers/acpi/ec.c | 12 ++++++++++-- > drivers/acpi/osl.c | 38 +++++++++++++++++++------------------- > drivers/acpi/pci_link.c | 2 ++ > drivers/acpi/processor_idle.c | 14 ++++++++++++-- > include/acpi/platform/aclinux.h | 6 ++++++ > 7 files changed, 77 insertions(+), 37 deletions(-) > > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
