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author | kib <kib@FreeBSD.org> | 2015-05-09 12:28:48 +0000 |
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committer | kib <kib@FreeBSD.org> | 2015-05-09 12:28:48 +0000 |
commit | 6006bf3a7dfd2f9b0bf0be6700967a1ab993b8a0 (patch) | |
tree | 4fbee808b24332d8ef01cb71eaaf6ca38551cfb9 /share/man/man4/acpi.4 | |
parent | 4f7fc385cadf246ec334db975b16c0e1743e87da (diff) | |
download | FreeBSD-src-6006bf3a7dfd2f9b0bf0be6700967a1ab993b8a0.zip FreeBSD-src-6006bf3a7dfd2f9b0bf0be6700967a1ab993b8a0.tar.gz |
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
Diffstat (limited to 'share/man/man4/acpi.4')
-rw-r--r-- | share/man/man4/acpi.4 | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/share/man/man4/acpi.4 b/share/man/man4/acpi.4 index 17cf1cb..8c221be 100644 --- a/share/man/man4/acpi.4 +++ b/share/man/man4/acpi.4 @@ -25,7 +25,7 @@ .\" .\" $FreeBSD$ .\" -.Dd June 23, 2014 +.Dd May 9, 2015 .Dt ACPI 4 .Os .Sh NAME @@ -69,14 +69,12 @@ them (such as Enable dumping Debug objects without .Cd "options ACPI_DEBUG" . Default is 0, ignore Debug objects. -.It Va hw.acpi.acline -AC line state (1 means online, 0 means on battery power). -.It Va hw.acpi.cpu.cx_usage +.It Va dev.cpu.N.cx_usage Debugging information listing the percent of total usage for each sleep state. The values are reset when -.Va hw.acpi.cpu.cx_lowest +.Va dev.cpu.N.cx_lowest is modified. -.It Va hw.acpi.cpu.cx_lowest +.It Va dev.cpu.N.cx_lowest Lowest Cx state to use for idling the CPU. A scheduling algorithm will select states between .Li C1 @@ -111,6 +109,11 @@ semantics as the state. Deeper sleeps provide more power savings but increased transition latency when an interrupt occurs. +.It Va dev.cpu.N.cx_method +List of supported CPU idle states and their transition methods, as +directed by the firmware. +.It Va hw.acpi.acline +AC line state (1 means online, 0 means on battery power). .It Va hw.acpi.disable_on_reboot Disable ACPI during the reboot process. Most systems reboot fine with ACPI still enabled, but some require @@ -374,6 +377,14 @@ typically as a child of a PCI bus. .Pq Vt device Supports an ACPI laptop lid switch, which typically puts a system to sleep. +.It Li mwait +.Pq Vt feature +Do not ask firmware for available x86-vendor specific methods to enter +.Li Cx +sleep states. +Only query and use the generic I/O-based entrance method. +The knob is provided to work around inconsistencies in the tables +filled by firmware. .It Li quirks .Pq Vt feature Do not honor quirks. |