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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-12 13:14:19 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-12 13:14:19 -0700 |
commit | 19c1940feab777bb037c665a09f495d08a6c4e6c (patch) | |
tree | 68d4de31f30c9d69a1f1ea080b8a69ce61e1ead5 /Documentation/cpu-freq | |
parent | 7c574cf6aeb75920ba4d3af937bb1b3c42785ac4 (diff) | |
parent | d715a226b0b3dae48865d05e8c36175a8f75a809 (diff) | |
download | op-kernel-dev-19c1940feab777bb037c665a09f495d08a6c4e6c.zip op-kernel-dev-19c1940feab777bb037c665a09f495d08a6c4e6c.tar.gz |
Merge tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more ACPI and power management updates from Rafael Wysocki:
"These are fixups on top of the previous PM+ACPI pull request,
regression fixes (ACPI hotplug, cpufreq ppc-corenet), other bug fixes
(ACPI reset, cpufreq), new PM trace points for system suspend
profiling and a copyright notice update.
Specifics:
- I didn't remember correctly that the Hans de Goede's ACPI video
patches actually didn't flip the video.use_native_backlight
default, although we had discussed that and decided to do that.
Since I said we would do that in the previous PM+ACPI pull request,
make that change for real now.
- ACPI bus check notifications for PCI host bridges don't cause the
bus below the host bridge to be checked for changes as they should
because of a mistake in the ACPI-based PCI hotplug (ACPIPHP)
subsystem that forgets to add hotplug contexts to PCI host bridge
ACPI device objects. Create hotplug contexts for PCI host bridges
too as appropriate.
- Revert recent cpufreq commit related to the big.LITTLE cpufreq
driver that breaks arm64 builds.
- Fix for a regression in the ppc-corenet cpufreq driver introduced
during the 3.15 cycle and causing the driver to use the remainder
from do_div instead of the quotient. From Ed Swarthout.
- Resets triggered by panic activate a BUG_ON() in vmalloc.c on
systems where the ACPI reset register is located in memory address
space. Fix from Randy Wright.
- Fix for a problem with cpufreq governors that decisions made by
them may be suboptimal due to the fact that deferrable timers are
used by them for CPU load sampling. From Srivatsa S Bhat.
- Fix for a problem with the Tegra cpufreq driver where the CPU
frequency is temporarily switched to a "stable" level that is
different from both the initial and target frequencies during
transitions which causes udelay() to expire earlier than it should
sometimes. From Viresh Kumar.
- New trace points and rework of some existing trace points for
system suspend/resume profiling from Todd Brandt.
- Assorted cpufreq fixes and cleanups from Stratos Karafotis and
Viresh Kumar.
- Copyright notice update for suspend-and-cpuhotplug.txt from
Srivatsa S Bhat"
* tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / hotplug / PCI: Add hotplug contexts to PCI host bridges
PM / sleep: trace events for device PM callbacks
cpufreq: cpufreq-cpu0: remove dependency on THERMAL and REGULATOR
cpufreq: tegra: update comment for clarity
cpufreq: intel_pstate: Remove duplicate CPU ID check
cpufreq: Mark CPU0 driver with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag
PM / Documentation: Update copyright in suspend-and-cpuhotplug.txt
cpufreq: governor: remove copy_prev_load from 'struct cpu_dbs_common_info'
cpufreq: governor: Be friendly towards latency-sensitive bursty workloads
PM / sleep: trace events for suspend/resume
cpufreq: ppc-corenet-cpu-freq: do_div use quotient
Revert "cpufreq: Enable big.LITTLE cpufreq driver on arm64"
cpufreq: Tegra: implement intermediate frequency callbacks
cpufreq: add support for intermediate (stable) frequencies
ACPI / video: Change the default for video.use_native_backlight to 1
ACPI: Fix bug when ACPI reset register is implemented in system memory
Diffstat (limited to 'Documentation/cpu-freq')
-rw-r--r-- | Documentation/cpu-freq/cpu-drivers.txt | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt index b045fe5..14f4e63 100644 --- a/Documentation/cpu-freq/cpu-drivers.txt +++ b/Documentation/cpu-freq/cpu-drivers.txt @@ -26,6 +26,7 @@ Contents: 1.4 target/target_index or setpolicy? 1.5 target/target_index 1.6 setpolicy +1.7 get_intermediate and target_intermediate 2. Frequency Table Helpers @@ -79,6 +80,10 @@ cpufreq_driver.attr - A pointer to a NULL-terminated list of "struct freq_attr" which allow to export values to sysfs. +cpufreq_driver.get_intermediate +and target_intermediate Used to switch to stable frequency while + changing CPU frequency. + 1.2 Per-CPU Initialization -------------------------- @@ -151,7 +156,7 @@ Some cpufreq-capable processors switch the frequency between certain limits on their own. These shall use the ->setpolicy call -1.4. target/target_index +1.5. target/target_index ------------- The target_index call has two arguments: struct cpufreq_policy *policy, @@ -160,6 +165,9 @@ and unsigned int index (into the exposed frequency table). The CPUfreq driver must set the new frequency when called here. The actual frequency must be determined by freq_table[index].frequency. +It should always restore to earlier frequency (i.e. policy->restore_freq) in +case of errors, even if we switched to intermediate frequency earlier. + Deprecated: ---------- The target call has three arguments: struct cpufreq_policy *policy, @@ -179,7 +187,7 @@ Here again the frequency table helper might assist you - see section 2 for details. -1.5 setpolicy +1.6 setpolicy --------------- The setpolicy call only takes a struct cpufreq_policy *policy as @@ -190,6 +198,23 @@ setting when policy->policy is CPUFREQ_POLICY_PERFORMANCE, and a powersaving-oriented setting when CPUFREQ_POLICY_POWERSAVE. Also check the reference implementation in drivers/cpufreq/longrun.c +1.7 get_intermediate and target_intermediate +-------------------------------------------- + +Only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION unset. + +get_intermediate should return a stable intermediate frequency platform wants to +switch to, and target_intermediate() should set CPU to to that frequency, before +jumping to the frequency corresponding to 'index'. Core will take care of +sending notifications and driver doesn't have to handle them in +target_intermediate() or target_index(). + +Drivers can return '0' from get_intermediate() in case they don't wish to switch +to intermediate frequency for some target frequency. In that case core will +directly call ->target_index(). + +NOTE: ->target_index() should restore to policy->restore_freq in case of +failures as core would send notifications for that. 2. Frequency Table Helpers |