Replace all uses of current_cpu_data with this_cpu operations on the
per cpu structure cpu_info. The scala accesses are replaced with the
matching this_cpu ops which results in smaller and more efficient
code.
In the long run, it might be a good idea to remove cpu_data() macro
too and use per_cpu macro directly.
tj: updated description
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Go through x86 code and replace __get_cpu_var and get_cpu_var
instances that refer to a scalar and are not used for address
determinations.
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (53 commits)
ACPI: install ACPI table handler before any dynamic tables being loaded
ACPI / PM: Blacklist another machine that needs acpi_sleep=nonvs
ACPI: Page based coalescing of I/O remappings optimization
ACPI: Convert simple locking to RCU based locking
ACPI: Pre-map 'system event' related register blocks
ACPI: Add interfaces for ioremapping/iounmapping ACPI registers
ACPI: Maintain a list of ACPI memory mapped I/O remappings
ACPI: Fix ioremap size for MMIO reads and writes
ACPI / Battery: Return -ENODEV for unknown values in get_property()
ACPI / PM: Fix reference counting of power resources
Subject: [PATCH] ACPICA: Fix Scope() op in module level code
ACPI battery: support percentage battery remaining capacity
ACPI: Make Embedded Controller command timeout delay configurable
ACPI dock: move some functions to .init.text
ACPI: thermal: remove unused limit code
ACPI: static sleep_states[] and acpi_gts_bfs_check
ACPI: remove dead code
ACPI: delete dedicated MAINTAINERS entries for ACPI EC and BATTERY drivers
ACPI: Only processor needs CPU_IDLE
ACPICA: Update version to 20101013
...
This patch fixes the following warning. The function
longrun_cpu_init() is marked with __cpuinit which calls
longrun_get_policy() which is a __init function. So make
longrun_get_policy with __cpuinit.
WARNING: arch/x86/kernel/cpu/cpufreq/longrun.o(.cpuinit.text+0x4c5):
Section mismatch in reference from the function longrun_cpu_init() to
the function .init.text:longrun_get_policy()
The function __cpuinit longrun_cpu_init() references
a function __init longrun_get_policy().
If longrun_get_policy is only used by longrun_cpu_init then
annotate longrun_get_policy with a matching annotation.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Dave Jones <davej@redhat.com>
In each case, the function has an unsigned return type, but returns a
negative constant to indicate an error condition. Each function is only
called once. For nforce2_detect_chipset, the result is only compared to 0,
and for longrun_determine_freqs, the result is stored in a variable of type
(signed) int. Thus, for both functions, unsigned can be dropped from the
return type.
A sematic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@exists@
identifier f;
constant C;
@@
unsigned f(...)
{ <+...
* return -C;
...+> }
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Dave Jones <davej@redhat.com>
If acpi_evaluate_object() function call doesn't fail, we must kfree()
output.buffer before returning from pcc_cpufreq_do_osc().
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dave Jones <davej@redhat.com>
acpi_perf_data is a percpu pointer but was missing __percpu markup.
Add it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>
pcc_cpu_info is a percpu pointer but was missing __percpu markup.
Add it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>
The only machines this is triggering on should be supported by
acpi-cpufreq or acpi's internal throttling.
Signed-off-by: Dave Jones <davej@redhat.com>
Use __cpuinit instead of __init for the cpufreq_driver
init function like it is done in powernow-k8.c.
This is removing the warning generated when compiling with
the CONFIG_DEBUG_SECTION_MISMATCH=y option.
Signed-off-by: Holger Hans Peter Freyther <holger@moiji-mobile.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Use __cpuinit instead of __init for the cpufreq_driver
init function like it is done in powernow-k8.c. Use the
__cpuinitdata for data used by the routines marked as __cpuinit.
This is removing the warning generated when compiling with
the CONFIG_DEBUG_SECTION_MISMATCH=y option.
Signed-off-by: Holger Hans Peter Freyther <holger@moiji-mobile.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Use __cpuinit instead of __init for the cpufreq_driver
init function like it is done in powernow-k8.c.
This is removing the warning generated when compiling with
the CONFIG_DEBUG_SECTION_MISMATCH=y option.
Signed-off-by: Holger Hans Peter Freyther <holger@moiji-mobile.com>
Signed-off-by: Dave Jones <davej@redhat.com>
rdmsr() takes the lower 32 bits as a second argument and the high 32 as
a third. Fix the names accordingly since they were swapped.
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This patch converts pci_table entries, where .subvendor=PCI_ANY_ID and
.subdevice=PCI_ANY_ID, .class=0 and .class_mask=0, to use the
PCI_VDEVICE macro, and thus improves readability.
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Dave Jones <davej@redhat.com>
and fix the broken case if a core's frequency depends on others.
trace_power_frequency was only implemented in a rather ungeneric way
in acpi-cpufreq driver's target() function only.
-> Move the call to trace_power_frequency to
cpufreq.c:cpufreq_notify_transition() where CPUFREQ_POSTCHANGE
notifier is triggered.
This will support power frequency tracing by all cpufreq drivers
trace_power_frequency did not trace frequency changes correctly when
the userspace governor was used or when CPU cores' frequency depend
on each other.
-> Moving this into the CPUFREQ_POSTCHANGE notifier and pass the cpu
which gets switched automatically fixes this.
Robert Schoene provided some important fixes on top of my initial
quick shot version which are integrated in this patch:
- Forgot some changes in power_end trace (TP_printk/variable names)
- Variable dummy in power_end must now be cpu_id
- Use static 64 bit variable instead of unsigned int for cpu_id
Signed-off-by: Thomas Renninger <trenn@suse.de>
CC: davej@redhat.com
CC: arjan@infradead.org
CC: linux-kernel@vger.kernel.org
CC: robert.schoene@tu-dresden.de
Tested-by: robert.schoene@tu-dresden.de
Signed-off-by: Dave Jones <davej@redhat.com>
On Wed, 2010-01-20 at 16:56 +0100, Thomas Renninger wrote:
> But most often this happens if people upgrade their CPU and do not
> update their BIOS.
> Or the vendor does not recognise the new CPU even if the BIOS got
> updated.
Maybe some of those people just didn't realize it was disabled in BIOS?
If you tell users that it's a firmware bug then they'll probably just
give up.
> The itself message might be an enhancment, IMO it's not worth a patch.
Why do you think so? I spent an hour on hunting down the BIOS upgrade,
only to find that it didn't improve anything. It was a day later that I
realized that it might be a BIOS option; and the option was literally
the _last_ option in the whole BIOS setup. :)
This message would have saved the day.
> But do not revert the FW_BUG part!
Sure, you have a point here.
How about this patch?
The Pstate transition latency check was added for broken F10h BIOSen
which wrongly contain a value of 0 for transition and bus master
latency. Fam11h and later, however, (will) have similar transition
latency so extend that behavior for them too.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The PCC cpufreq driver unmaps the mailbox address range if any CPUs fail to
initialise, but doesn't do anything to remove the registered CPUs from the
cpufreq core resulting in failures further down the line. We're better off
simply returning a failure - the cpufreq core will unregister us cleanly if
we end up with no successfully registered CPUs. Tidy up the failure path
and also add a sanity check to ensure that the firmware gives us a realistic
frequency - the core deals badly with that being set to 0.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The pcc specification documents an _OSC method that's incompatible with the
one defined as part of the ACPI spec. This shouldn't be a problem as both
are supposed to be guarded with a UUID. Unfortunately approximately nobody
(including HP, who wrote this spec) properly check the UUID on entry to the
_OSC call. Right now this could result in surprising behaviour if the pcc
driver performs an _OSC call on a machine that doesn't implement the pcc
specification. Check whether the PCCH method exists first in order to reduce
this probability.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The Pstate transition latency check was added for broken F10h BIOSen
which wrongly contain a value of 0 for transition and bus master
latency. Fam11h and later, however, (will) have similar transition
latency so extend that behavior for them too.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The PCC cpufreq driver unmaps the mailbox address range if any CPUs fail to
initialise, but doesn't do anything to remove the registered CPUs from the
cpufreq core resulting in failures further down the line. We're better off
simply returning a failure - the cpufreq core will unregister us cleanly if
we end up with no successfully registered CPUs. Tidy up the failure path
and also add a sanity check to ensure that the firmware gives us a realistic
frequency - the core deals badly with that being set to 0.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
The pcc specification documents an _OSC method that's incompatible with the
one defined as part of the ACPI spec. This shouldn't be a problem as both
are supposed to be guarded with a UUID. Unfortunately approximately nobody
(including HP, who wrote this spec) properly check the UUID on entry to the
_OSC call. Right now this could result in surprising behaviour if the pcc
driver performs an _OSC call on a machine that doesn't implement the pcc
specification. Check whether the PCCH method exists first in order to reduce
this probability.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
pavel@suse.cz no longer works, replace it with working address.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Fix the following warning:
"WARNING: arch/x86/kernel/built-in.o(.exit.text+0x72):
Section mismatch in reference from the function powernowk8_exit() to the variable .cpuinit.data:cpb_nb
The function __exit powernowk8_exit() references a variable
__cpuinitdata cpb_nb. This is often seen when error handling in the exit
function uses functionality in the init path. The fix is often to remove
the __cpuinitdata annotation of cpb_nb so it may be used outside an init
section."
Cc: <stable@kernel.org>
Reported-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100525152858.GA24836@aftab>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
With F10, model 10, all valid frequencies are in the ACPI _PST table.
Cc: <stable@kernel.org> # 33.x 32.x
Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com>
LKML-Reference: <1270065406-1814-6-git-send-email-bp@amd64.org>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Starting with model 10 of Family 0x10, AMD processors may have
support for APERF/MPERF. Add support for identifying it and using
it within cpufreq. Move the APERF/MPERF functions out of the
acpi-cpufreq code and into their own file so they can easily be
shared.
Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com>
LKML-Reference: <20100401141956.GA1930@aftab>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Starting with F10h, revE, AMD processors add support for a dynamic
core boosting feature called Core Performance Boost. When a specific
condition is present, a subset of the cores on a system are boosted
beyond their P0 operating frequency to speed up the performance of
single-threaded applications.
In the normal case, the system comes out of reset with core boosting
enabled. This patch adds a sysfs knob with which core boosting can be
switched on or off for benchmarking purposes.
While at it, make the CPB code hotplug-aware so that taking cores
offline wouldn't interfere with boosting the remaining online cores.
Furthermore, add cpu_online_mask hotplug protection as suggested by
Andrew.
Finally, cleanup the driver init codepath and update copyrights.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1270065406-1814-3-git-send-email-bp@amd64.org>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* 'acpica' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI: replace acpi_integer by u64
ACPICA: Update version to 20100121.
ACPICA: Remove unused uint32_struct type
ACPICA: Disassembler: Remove obsolete "Integer64" field in parse object
ACPICA: Remove obsolete ACPI_INTEGER (acpi_integer) type
ACPICA: Predefined name repair: fix NULL package elements
ACPICA: AcpiGetDevices: Eliminate unnecessary _STA calls
ACPICA: Update all ACPICA copyrights and signons to 2010
ACPICA: Update for new gcc-4 warning options
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] Fix ondemand to not request targets outside policy limits
[CPUFREQ] Fix use after free of struct powernow_k8_data
[CPUFREQ] fix default value for ondemand governor
acpi_integer is now obsolete and removed from the ACPICA code base,
replaced by u64.
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Processor Clocking Control (PCC) is an interface between the BIOS and OSPM.
Based on the server workload, OSPM can request what frequency it expects
from a logical CPU, and the BIOS will achieve that frequency transparently.
This patch introduces driver support for PCC. OSPM uses the PCC driver to
communicate with the BIOS via the PCC interface.
There is a Documentation file that provides a link to the PCC
Specification, and also provides a summary of the PCC interface.
Currently, certain HP ProLiant platforms implement the PCC interface. However,
any platform whose BIOS implements the PCC Specification, can utilize this
driver.
V2 --> V1 changes (based on Dominik's suggestions):
- Removed the dependency on CPU_FREQ_TABLE
- "cpufreq_stats" will no longer PANIC. Actually, it will not load anymore
because it is not applicable.
- Removed the sanity check for target frequency in the ->target routine.
NOTE: A patch to sanitize the target frequency requested by "ondemand" is
needed to ensure that the target freq < policy->min.
Can this driver be queued up for the 2.6.33 tree?
Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
Easy fix for a regression introduced in 2.6.31.
On managed CPUs the cpufreq.c core will call driver->exit(cpu) on the
managed cpus and powernow_k8 will free the core's data.
Later driver->get(cpu) function might get called trying to read out the
current freq of a managed cpu and the NULL pointer check does not work on
the freed object -> better set it to NULL.
->get() is unsigned and must return 0 as invalid frequency.
Reference:
http://bugzilla.kernel.org/show_bug.cgi?id=14391
Signed-off-by: Thomas Renninger <trenn@suse.de>
Tested-by: Michal Schmidt <mschmidt@redhat.com>
CC: stable@kernel.org
Signed-off-by: Dave Jones <davej@redhat.com>
Presently acpi-cpufreq will perform the MSR read on the first CPU in the
mask. That's inefficient if that CPU differs from the current CPU.
Because we have to perform a cross-CPU call, but we could have run the
rdmsr on the current CPU.
So switch to using the new smp_call_function_any(), which will perform the
call on the current CPU if that CPU is present in the mask (it is).
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Noone uses this wrapper yet, and Ingo asked that it be kept consistent
with current task_struct usage.
(One user crept in via linux-next: fixed)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...
Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[ACPI/CPUFREQ] Introduce bios_limit per cpu cpufreq sysfs interface
[CPUFREQ] make internal cpufreq_add_dev_* static
[CPUFREQ] use an enum for speedstep processor identification
[CPUFREQ] Document units for transition latency
[CPUFREQ] Use global sysfs cpufreq structure for conservative governor tunings
[CPUFREQ] Documentation: ABI: /sys/devices/system/cpu/cpu#/cpufreq/
[CPUFREQ] powernow-k6: set transition latency value so ondemand governor can be used
[CPUFREQ] cpumask: don't put a cpumask on the stack in x86...cpufreq/powernow-k8.c
The existing interface only has a pre-order callback. This change
adds an additional parameter for a post-order callback which will
be more useful for bus scans. ACPICA BZ 779.
Also update the external calls to acpi_walk_namespace.
http://www.acpica.org/bugzilla/show_bug.cgi?id=779
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This interface is mainly intended (and implemented) for ACPI _PPC BIOS
frequency limitations, but other cpufreq drivers can also use it for
similar use-cases.
Why is this needed:
Currently it's not obvious why cpufreq got limited.
People see cpufreq/scaling_max_freq reduced, but this could have
happened by:
- any userspace prog writing to scaling_max_freq
- thermal limitations
- hardware (_PPC in ACPI case) limitiations
Therefore export bios_limit (in kHz) to:
- Point the user that it's the BIOS (broken or intended) which limits
frequency
- Export it as a sysfs interface for userspace progs.
While this was a rarely used feature on laptops, there will appear
more and more server implemenations providing "Green IT" features like
allowing the service processor to limit the frequency. People want
to know about HW/BIOS frequency limitations.
All ACPI P-state driven cpufreq drivers are covered with this patch:
- powernow-k8
- powernow-k7
- acpi-cpufreq
Tested with a patched DSDT which limits the first two cores (_PPC returns 1)
via _PPC, exposed by bios_limit:
# echo 2200000 >cpu2/cpufreq/scaling_max_freq
# cat cpu*/cpufreq/scaling_max_freq
2600000
2600000
2200000
2200000
# #scaling_max_freq shows general user/thermal/BIOS limitations
# cat cpu*/cpufreq/bios_limit
2600000
2600000
2800000
2800000
# #bios_limit only shows the HW/BIOS limitation
CC: Pallipadi Venkatesh <venkatesh.pallipadi@intel.com>
CC: Len Brown <lenb@kernel.org>
CC: davej@codemonkey.org.uk
CC: linux@dominikbrodowski.net
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
Tejun Heo