If x86 CPU implementation of the MWAIT instruction reasonably

interacts with interrupts, query ACPI and use MWAIT for entrance into
Cx sleep states.  Support C1 "I/O then halt" mode.  See Intel'
document 302223-007 "Intelб╝ Processor Vendor-Specific ACPI Interface
Specification" for description.

Move the acpi_cpu_c1() function into x86/cpu_machdep.c and use
it instead of inlining "sti; hlt" sequence in several places.

In the acpi(4) man page, besides documenting the dev.cpu.N.cx_methods
sysctl, correct the names for dev.cpu.N.{cx_usage,cx_lowest,cx_supported}
sysctls.

Both jkim and avg have some other patches implementing the mwait
functionality; this work is unrelated.  Linux does not rely on the
ACPI to provide correct tables describing Cx modes.  Instead, the
driver has pre-defined knowledge of the CPU models, it was supplied by
Intel.

Tested by:    pho (previous versions)
Sponsored by:	The FreeBSD Foundation

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/x86/include/acpica_machdep.h b/sys/x86/include/acpica_machdep.h
index 46080c0..136285c 100644
--- a/sys/x86/include/acpica_machdep.h
+++ b/sys/x86/include/acpica_machdep.h
@@ -74,6 +74,7 @@ enum intr_polarity;
 
 void	acpi_SetDefaultIntrModel(int model);
 void	acpi_cpu_c1(void);
+void	acpi_cpu_idle_mwait(uint32_t mwait_hint);
 void	*acpi_map_table(vm_paddr_t pa, const char *sig);
 void	acpi_unmap_table(void *table);
 vm_paddr_t acpi_find_table(const char *sig);