linux-toradex.git/include/linux/cpufreq.h, branch v2.6.29

Revert "[CPUFREQ] Disable sysfs ui for p4-clockmod."

2009-03-09T19:07:33+00:00

This reverts commit e088e4c9cdb618675874becb91b2fd581ee707e6.

Removing the sysfs interface for p4-clockmod was flagged as a
regression in bug 12826.

Course of action:
 - Find out the remaining causes of overheating, and fix them
   if possible. ACPI should be doing the right thing automatically.
   If it isn't, we need to fix that.
 - mark p4-clockmod ui as deprecated
 - try again with the removal in six months.

It's not really feasible to printk about the deprecation, because
it needs to happen at all the sysfs entry points, which means adding
a lot of strcmp("p4-clockmod".. calls to the core, which.. bleuch.

Signed-off-by: Dave Jones

cpumask: convert struct cpufreq_policy to cpumask_var_t

2009-01-06T08:05:31+00:00

Impact: use new cpumask API to reduce memory usage

This is part of an effort to reduce structure sizes for machines
configured with large NR_CPUS.  cpumask_t gets replaced by
cpumask_var_t, which is either struct cpumask[1] (small NR_CPUS) or
struct cpumask * (large NR_CPUS).

Signed-off-by: Rusty Russell 
Signed-off-by: Mike Travis 
Acked-by: Dave Jones 
Signed-off-by: Ingo Molnar

[CPUFREQ] Disable sysfs ui for p4-clockmod.

2008-12-05T20:20:10+00:00

p4-clockmod has a long history of abuse.   It pretends to be a CPU
frequency scaling driver, even though it doesn't actually change
the CPU frequency, but instead just modulates the frequency with
wait-states.
The biggest misconception is that when running at the lower 'frequency'
p4-clockmod is saving power.  This isn't the case, as workloads running
slower take longer to complete, preventing the CPU from entering deep C states.

However p4-clockmod does have a purpose.  It can prevent overheating.
Having it hooked up to the cpufreq interfaces is the wrong way to achieve
cooling however. It should instead be hooked up to ACPI.

This diff introduces a means for a cpufreq driver to register with the
cpufreq core, but not present a sysfs interface.

Signed-off-by: Matthew Garrett 
Signed-off-by: Dave Jones

[CPUFREQ][1/6] cpufreq: Add cpu number parameter to __cpufreq_driver_getavg()

2008-10-09T17:52:43+00:00

Add a cpu parameter to __cpufreq_driver_getavg(). This is needed for software
cpufreq coordination where policy->cpu may not be same as the CPU on which we
want to getavg frequency.

A follow-on patch will use this parameter to getavg freq from all cpus
in policy->cpus.

Change since last patch. Fix the offline/online and suspend/resume
oops reported by Youquan Song 

Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Dave Jones

cpufreq acpi: only call _PPC after cpufreq ACPI init funcs got called already

2008-07-30T16:41:43+00:00

Ingo Molnar provided a fix to not call _PPC at processor driver
initialization time in "[PATCH] ACPI: fix cpufreq regression" (git
commit e4233dec749a3519069d9390561b5636a75c7579)

But it can still happen that _PPC is called at processor driver
initialization time.

This patch should make sure that this is not possible anymore.

Signed-off-by: Thomas Renninger 
Cc: Andi Kleen 
Cc: Len Brown 
Cc: Dave Jones 
Cc: Ingo Molnar 
Cc: Venkatesh Pallipadi 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[CPUFREQ] cpufreq: remove CVS keywords

2008-05-19T22:17:49+00:00

This patch removes CVS keywords that weren't updated for a long time
from comments.

Signed-off-by: Adrian Bunk 
Signed-off-by: Dave Jones

[CPUFREQ] allow use of the powersave governor as the default one

2008-04-28T20:27:08+00:00

Allow use of the powersave cpufreq governor as the default one for EMBEDDED
configs.

Signed-off-by: Alessandro Guido 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Jones

[CPUFREQ] expose cpufreq coordination requirements regardless of coordination mechanism

2008-04-28T20:27:08+00:00

Currently, affected_cpus shows which CPUs need to have their frequency
coordinated in software.  When hardware coordination is in use, the contents
of this file appear the same as when no coordination is required.  This can
lead to some confusion among user-space programs, for example, that do not
know that extra coordination is required to force a CPU core to a particular
speed to control power consumption.

To fix this, create a "related_cpus" attribute that always displays the
coordination map regardless of whatever coordination strategy the cpufreq
driver uses (sw or hw).  If the cpufreq driver does not provide a value, fall
back to policy->cpus.

Signed-off-by: Darrick J. Wong 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Jones

[CPUFREQ] Eliminate cpufreq_userspace scaling_setspeed deadlock

2008-02-07T03:57:58+00:00

Eliminate cpufreq_userspace scaling_setspeed deadlock.

Luming Yu recently uncovered yet another cpufreq related deadlock.
One thread that continuously switches the governors and the other thread that
repeatedly cats the contents of cpufreq directory causes both these threads to
go into a deadlock.

Detailed examination of the deadlock showed the exact flow before the deadlock
as:

Thread 1			Thread 2
________			________
				cats files under /sys/devices/.../cpufreq/
Set governor to userspace
  Adds a new sysfs entry for
  scaling_setspeed
				cats files under /sys/devices/.../cpufreq/

Set governor to performance
  Holds cpufreq_rw_sem in write
  mode
  Sends a STOP notify to
  userspace governor
				cat /sys/devices/.../cpufreq/scaling_setspeed
				  Gets a handle on the above sysfs entry with
				  sysfs_get_active
				  Blocks while trying to get cpufreq_rw_sem
				  in read mode
  Remove a sysfs entry for
  scaling_setspeed
    Blocks on sysfs_deactivate
    while waiting for earlier
    get_active (on other thread)
    to drain

At this point both threads go into deadlock and any other thread that tries to
do anything with sysfs cpufreq will also block.

There seems to be no easy way to avoid this deadlock as long as
cpufreq_userspace adds/removes the sysfs entry under same kobject as cpufreq.
Below patch moves scaling_setspeed to cpufreq.c, keeping it always and calling
back the governor on read/write. This is the cleanest fix I could think of,
even though adding two callbacks in governor structure just for this seems
unnecessary.

Note that the change makes scaling_setspeed under /sys/.../cpufreq permanent
and returns  when governor is not userspace.

Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Dave Jones

[CPUFREQ] implement !CONFIG_CPU_FREQ stub for cpufreq_unregister_notifier()

2007-10-04T22:40:57+00:00

Callsites such as arch/powerpc/oprofile/op_model_cell.c are having to
open-code #ifdef CONFIG_CPU_FREQ only to be able to get at the full definition
of cpufreq_unregister_notifier(), because no empty stub is available for the
!CONFIG_CPU_FREQ case.  Let's provide one, to be able to remove such #ifdef's
from the rest of the kernel tree -- those will come in a subsequent patch.

Signed-off-by: Satyam Sharma 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Jones