On Wed, 4 Dec 2013 14:22:03 -0700, al.stone@xxxxxxxxxx wrote: > From: Al Stone <al.stone@xxxxxxxxxx> > > To enable the hardware reduced mode of ACPI on some platforms (such as > ARM), we need to modify the kernel code and set ACPI_REDUCED_HARDWARE > to TRUE in the ACPICA source. > > This can be done more resonably by introducing a kernel config item > to enable/disable ACPI_REDUCED_HARDWARE. We can then change the kernel > config instead of having to modify the kernel source directly to enable > the reduced hardware mode of ACPI. > > Lv Zheng suggested that this configuration item does not belong in ACPICA, > the upstream source for much of the ACPI internals, but rather to the > Linux kernel itself. Hence, we introduce this flag so that we can make > ACPI_REDUCED_HARDWARE configurable. For the details of the discussion, > please refer to: http://www.spinics.net/lists/linux-acpi/msg46369.html > > Support for X86 in hardware reduced mode is also provided to make it > simpler to debug this mode, and to provide for probable use in such > products. Hardware reduced mode, despite the name, exists primarily > to allow newer platforms to use a much simpler form of ACPI that does > not require supporting the legacy of previous versions of the specification, > and is likely to be used more often in the near future as a result. > > Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx> > Signed-off-by: Al Stone <al.stone@xxxxxxxxxx> > --- > drivers/acpi/Kconfig | 8 ++++++++ > include/acpi/platform/aclinux.h | 6 ++++++ > 2 files changed, 14 insertions(+) > > diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig > index 5d92485..66e6bb2 100644 > --- a/drivers/acpi/Kconfig > +++ b/drivers/acpi/Kconfig > @@ -343,6 +343,14 @@ config ACPI_BGRT > data from the firmware boot splash. It will appear under > /sys/firmware/acpi/bgrt/ . > > +config ACPI_REDUCED_HARDWARE > + bool "Hardware-reduced ACPI support" > + depends on X86 || ARM || ARM64 > + help > + This config adds support for Hardware-reduced ACPI. When this option > + is selected, will generate a specialized version of ACPICA that ONLY > + supports the ACPI "reduced hardware". > + > source "drivers/acpi/apei/Kconfig" > > config ACPI_EXTLOG > diff --git a/include/acpi/platform/aclinux.h b/include/acpi/platform/aclinux.h > index 28f4f4d..a33f502 100644 > --- a/include/acpi/platform/aclinux.h > +++ b/include/acpi/platform/aclinux.h > @@ -52,6 +52,12 @@ > > #ifdef __KERNEL__ > > +/* Compile for reduced hardware mode if requested for this kernel config */ > + > +#ifdef CONFIG_ACPI_REDUCED_HARDWARE > +#define ACPI_REDUCED_HARDWARE 1 > +#endif Will this change the way ACPICA is compiled? Will it disable non-hardware-reduced mode? If so, then this is a big problem. Enabling the hardware reduced feature should *not* break normal ACPI usage. g. -- 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
