2613 Commits

Author SHA1 Message Date
d306ebc286 ACPI: Be in TS_POLLING state during mwait based C-state entry
ACPI deep C-state entry had a long standing bug/missing feature, wherein we were sending
resched IPIs when an idle CPU is in mwait based deep C-state. Only mwait based C1 was using
the write to the monitored address to wake up mwait'ing CPU.

This patch changes the code to retain TS_POLLING bit if we are entering an mwait based
deep C-state.

The patch has been verified to reduce the number of resched IPIs in general and also
improves the performance/power on workloads with low system utilization (i.e., when mwait based
deep C-states are being used).

Fixes "netperf ~50% regression with 2.6.33-rc1, bisect to 1b9508f"
http://marc.info/?l=linux-kernel&m=126441481427331&w=4

Reported-by: Lin Ming <ming.m.lin@intel.com>
Tested-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-22 13:10:14 -05:00
8b7ef6d8f1 ACPI thermal: Check for thermal zone requirement
ACPI spec says (11.5 Thermal Zone Interface Requirements):
   A thermal zone must contain at least one trip point
   (critical, near critical, active, or passive)

Check this once at init time.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Tested-by: clarkt@cnsp.com
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-19 01:48:48 -05:00
455c0d71d4 ACPI: Fix regression where _PPC is not read at boot even when ignore_ppc=0
Earlier, Ingo Molnar posted a patch to make it so that the kernel would avoid
reading _PPC on his broken T60.  Unfortunately, it seems that with Thomas
Renninger's patch last July to eliminate _PPC evaluations when the processor
driver loads, the kernel never actually reads _PPC at all!  This is problematic
if you happen to boot your non-T60 computer in a state where the BIOS _wants_
_PPC to be something other than zero.

So, put the _PPC evaluation back into acpi_processor_get_performance_info if
ignore_ppc isn't 1.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-19 01:11:48 -05:00
0e2ecbaefd Merge branches 'bugzilla-14886', 'bugzilla-15000', 'bugzilla-15040', 'bugzilla-15108', 'pdc', 'hotplug-null-ref' and 'thinkpad' into release 2010-02-18 03:51:04 -05:00
49bf83a45f ACPI: fix "acpi=ht" boot option
We broke "acpi=ht" in 2.6.32 by disabling MADT parsing
for acpi=disabled.  e5b8fc6ac158f65598f58dba2c0d52ba3b412f52
This also broke systems which invoked acpi=ht via DMI blacklist.

acpi=ht is a really ugly hack,
but restore it for those that still use it.

http://bugzilla.kernel.org/show_bug.cgi?id=14886

Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-18 03:49:38 -05:00
2b633e3fac smp: Use nr_cpus= to set nr_cpu_ids early
On x86, before prefill_possible_map(), nr_cpu_ids will be NR_CPUS aka
CONFIG_NR_CPUS.

Add nr_cpus= to set nr_cpu_ids. so we can simulate cpus <=8 are installed on
normal config.

-v2: accordging to Christoph, acpi_numa_init should use nr_cpu_ids in stead of
     NR_CPUS.
-v3: add doc in kernel-parameters.txt according to Andrew.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-34-git-send-email-yinghai@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Tony Luck <tony.luck@intel.com>
2010-02-17 17:30:22 -08:00
a29d8b8e2d percpu: add __percpu sparse annotations to what's left
Add __percpu sparse annotations to places which didn't make it in one
of the previous patches.  All converions are trivial.

These annotations are to make sparse consider percpu variables to be
in a different address space and warn if accessed without going
through percpu accessors.  This patch doesn't affect normal builds.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Neil Brown <neilb@suse.de>
2010-02-17 11:17:38 +09:00
370d5cd885 ACPI: fix High cpu temperature with 2.6.32
Since the rewrite of the CPU idle governor in 2.6.32, two laptops have
surfaced where the BIOS advertises a C2 power state, but for some reason
this state is not functioning (as verified in both cases by powertop
before the patch in .32).

The old governor had the accidental behavior that if a non-working state
was chosen too many times, it would end up falling back to C1.  The new
governor works differently and this accidental behavior is no longer
there; the result is a high temperature on these two machines.

This patch adds these 2 machines to the DMI table for C state anomalies;
by just not using C2 both these machines are better off (the TSC can be
used instead of the pm timer, giving a performance boost for example).

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14742

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Reported-by: <akwatts@ymail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-16 04:11:27 -05:00
49c6fb2e41 ACPI: dock: properly initialize local struct dock_station in dock_add()
Commit fe06fba2 (ACPI: dock: add struct dock_station * directly
to platform device data) changed dock_add() to use the
platform_device_register_data() API.

We passed that interface a stack variable, which is kmemdup'ed
and assigned to the device's platform_data pointer.

Unfortunately, whatever random garbage is in the stack variable
gets coped during the kmemdup, and that leads to broken behavior.

Explicitly zero out the structure before passing it to the API.

This fixes the T41 docking button issue:
http://bugzilla.kernel.org/show_bug.cgi?id=15000

Cc: stable@kernel.org
Reported-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-16 03:54:28 -05:00
38bcb37a6f ACPICA: fix acpi_ex_release_mutex() comment
trivial, leftover from my NULL pointer dereference patch which got
'superseded' by commit fbc3be2

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-16 03:17:42 -05:00
ded180e7eb ACPI: remove superfluous NULL pointer check from acpi_processor_get_throttling_info()
Dan's list contains:

drivers/acpi/processor_throttling.c +1139 acpi_processor_get_throttling_info(11) warning: variable derefenced before check 'pr'

acpi_processor_get_throttling_info() is never called with pr == NULL.

[ bart: the potential NULL pointer dereference was finally fixed in
  (much later than mine) commit 5cfa245 but my patch is still valid ]

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-16 03:17:41 -05:00
0e026445fb ACPI: delete unused acpi_evaluate_string()
Roel found a logic issue in the #if 0 acpi_evaluate_string():

-           || (element->type != ACPI_TYPE_BUFFER)
+           && (element->type != ACPI_TYPE_BUFFER)

delete the dead code.

pointed-out-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-02-16 03:17:40 -05:00
3ad2f3fbb9 tree-wide: Assorted spelling fixes
In particular, several occurances of funny versions of 'success',
'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address',
'beginning', 'desirable', 'separate' and 'necessary' are fixed.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-02-09 11:13:56 +01:00
edf86baae2 Fix misspellings of "separate" in strings.
Some string messages misspell "separate"; this fixes them. No change in
functionality.

Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-02-04 11:55:46 +01:00
7779688fc3 ACPI: acpi_bus_{scan,bus,add}: return -ENODEV if no device was found
Callers (acpi_memhotplug.c, dock.c and others) check for the return
value of acpi_bus_add() and assume a valid device was returned in
case zero was returned.

Thus return -ENODEV if no device was found in acpi_bus_scan and
propagate this through acpi_bus_add and acpi_bus_start.

Also remove a confusing comment in acpiphp_glue.c, acpi_bus_scan
will and cannot invoke if acpi_bus_add returns no valid device.

Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-31 21:43:32 -05:00
d2f6650a95 ACPI: Add NULL pointer check in acpi_bus_start
If acpi_bus_add does not return a device and it's passed
to acpi_bus_start, bad things will happen:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffff8128402d>] acpi_bus_start+0x14/0x24
...
[<ffffffffa008977a>] acpiphp_bus_add+0xba/0x130 [acpiphp]
[<ffffffffa008aa72>] enable_device+0x132/0x2ff [acpiphp]
[<ffffffffa0089b68>] acpiphp_enable_slot+0xb8/0x130 [acpiphp]
[<ffffffffa0089df7>] handle_hotplug_event_func+0x87/0x190 [acpiphp]

Next patch would make this NULL pointer check obsolete, but
better having one more than one missing...

Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
CC: stable@kernel.org
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-31 21:43:04 -05:00
439913fffd ACPI: replace acpi_integer by u64
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>
2010-01-28 01:47:33 -05:00
a4932299d0 ACPI: processor: only evaluate _PDC once per processor
If we evaluate _PDC in the early path, we do not want to evaluate
it again when the processor driver is loaded.

Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:39:56 -05:00
0406ad336c ACPI: processor: add kernel command line support for early _PDC eval
Allow platforms not listed in DMI table
to opt-in and evaluate _PDC early.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:39:21 -05:00
758d49313d ACPICA: Disassembler: Remove obsolete "Integer64" field in parse object
This field is no longer needed. The "Integer" field is 64 bit
and is sufficient.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:30:08 -05:00
5df7e6cb42 ACPICA: Remove obsolete ACPI_INTEGER (acpi_integer) type
This type was introduced as the code was migrated from ACPI 1.0
(with 32-bit AML integers) to ACPI 2.0 (with 64-bit integers). It
is now obsolete and this change removes it from the ACPICA code
base, replaced by u64.  The original typedef has been retained
for now for compatibility with existing device driver code.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:30:06 -05:00
091f4d7186 ACPICA: Predefined name repair: fix NULL package elements
For the predefined methods that return fixed-length packages
(or subpackages), attempt repair for a NULL element. Create an
Integer of value 0, a NULL String, or a zero-length buffer as
appropriate.

http://www.acpica.org/bugzilla/show_bug.cgi?id=818

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:30:06 -05:00
5f8902acf8 ACPICA: AcpiGetDevices: Eliminate unnecessary _STA calls
In the case where a specific _HID is requested, do not run _STA
until a _HID match is found. This eliminates potentially dozens
of _STA calls during a search for a particular device/HID.

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>
2010-01-22 12:30:05 -05:00
a8357b0c95 ACPICA: Update all ACPICA copyrights and signons to 2010
Add 2010 copyright to all module headers and signons, including
the Linux header. This affects virtually every file in the ACPICA
core subsystem, iASL compiler, and all utilities.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:30:05 -05:00
2147d3f00f ACPICA: Update for new gcc-4 warning options
Added several new options for the gcc-4 generation, and updated
the source accordingly. This includes some code restructuring to
eliminate unreachable code, elimination of some gotos, elimination
of unused return values, and some additional casting.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-22 12:30:02 -05:00
418521deef Merge branch 'bugzilla-14954' into release 2010-01-20 01:26:22 -05:00
be6066f34c Merge branch 'misc' into release 2010-01-20 01:23:27 -05:00
b4cdd6ac4f Merge branch 'osc-bugfix' into release 2010-01-20 01:23:18 -05:00
b07f07e0c2 Merge branch 'ec' into release 2010-01-20 01:20:36 -05:00
361243fd62 Merge branch 'bugzilla-15064' into release 2010-01-20 01:15:21 -05:00
49897deeea Merge branch 'bugzilla-14858' into release 2010-01-20 01:14:57 -05:00
093e2961fe Merge branch 'bugzilla-13577-video' into release 2010-01-20 01:14:41 -05:00
9c6a6b3cbc Merge branch 'acpi-pad' into release 2010-01-20 01:14:30 -05:00
d22edd293f ACPI: delete acpi_processor_power_verify_c2()
no functional change -- cleanup only.

acpi_processor_power_verify_c2() was nearly empty due to a previous patch,
so expand its remains into its one caller and delete it.

Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-20 00:54:15 -05:00
a6d72c189f ACPI: allow C3 > 1000usec
Do for C3 what the previous patch did for C2.

The C2 patch was in response to a highly visible
and multiply reported C-state/turbo failure,
while this change has no bug report in-hand.

This will enable C3 in Linux on systems where BIOS
overstates C3 latency in _CST.  It will also enable
future systems which may actually have C3 > 1000usec.

Linux has always ignored ACPI BIOS C3 with exit latency > 1000 usec,
and the ACPI spec is clear that is correct FADT-supplied C3.

However, the ACPI spec explicitly states that _CST-supplied C-states
have no latency limits.

So move the 1000usec C3 test out of the code shared
by FADT and _CST code-paths, and into the FADT-specific path.

Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-20 00:54:15 -05:00
5d76b6f6c1 ACPI: enable C2 and Turbo-mode on Nehalem notebooks on A/C
Linux has always ignored ACPI BIOS C2 with exit latency > 100 usec,
and the ACPI spec is clear that is correct FADT-supplied C2.

However, the ACPI spec explicitly states that _CST-supplied C-states
have no latency limits.

So move the 100usec C2 test out of the code shared
by FADT and _CST code-paths, and into the FADT-specific path.

This bug has not been visible until Nehalem, which advertises
a CPU-C2 worst case exit latency on servers of 205usec.
That (incorrect) figure is being used by BIOS writers
on mobile Nehalem systems for the AC configuration.
Thus, Linux ignores C2 leaving just C1, which is
saves less power, and also impacts performance
by preventing the use of turbo mode.

http://bugzilla.kernel.org/show_bug.cgi?id=15064

Tested-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-20 00:54:01 -05:00
7f07a605a3 ACPI: power_meter: remove double kfree()
resource->domain_devices can be double kfree()'d in a couple of places.
Fix this by setting num_domain_devices = 0 after the kfree().

Coverity CID: 13356, 13355, 13354

Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>
Acked-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-19 23:56:02 -05:00
2205cbe8ec ACPI: processor: restrict early _PDC to opt-in platforms
Commit 78f1699 (ACPI: processor: call _PDC early) blindly walks
the namespace and calls _PDC on every processor object it finds.

This change may cause issues on platforms that declare dummy
values for SSDTs on non-present processors (disabled in MADT).
When we call _PDC and dynamically attempt to execute the AML
Load() op on these dummy SSDTs, there's no telling what might
happen.

Rather than finding every platform that has bogus SSDTs, restrict
early _PDC calls to platforms that are known to need early
evaluation of _PDC.

This is a minimal, temporary fix (given the context of the
current release cycle). A real solution of checking the MADT for
non-present processors will be written for the next merge window.

References:

	http://bugzilla.kernel.org/show_bug.cgi?id=14710
	http://bugzilla.kernel.org/show_bug.cgi?id=14954

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-19 23:43:47 -05:00
c19bdb6126 ACPI: Fix unused variable warning in sbs.c
When CONFIG_ACPI_SYSFS_POWER=n and CONFIG_ACPI_PROCFS_POWER=n, then
we're warned by the following warning:

drivers/acpi/sbs.c: In function `acpi_battery_remove':
drivers/acpi/sbs.c:825: warning: unused variable `battery'

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-16 16:04:18 -05:00
c97adf9e7b acpi: make ACPI device id constant
The ids field of the struct acpi_driver is constant in <linux/acpi/acpi_bus.h>
so it is worth to make the initialization data also constant.

The semantic match that finds this kind of pattern is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
disable decl_init,const_decl_init;
identifier I1, I2, x;
@@
	struct I1 {
	  ...
	  const struct I2 *x;
	  ...
	};
@s@
identifier r.I1, y;
identifier r.x, E;
@@
	struct I1 y = {
	  .x = E,
	};
@c@
identifier r.I2;
identifier s.E;
@@
	const struct I2 E[] = ... ;
@depends on !c@
identifier r.I2;
identifier s.E;
@@
+	const
	struct I2 E[] = ...;
// </smpl>

Signed-off-by: Márton Németh <nm127@freemail.hu>
Cc: Julia Lawall <julia@diku.dk>
Cc: cocci@diku.dk
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-16 15:56:43 -05:00
7a0b73a49a ACPI: Fix section mismatch error for acpi_early_processor_set_pdc()
Alex Chiang introduced acpi_early_processor_set_pdc() in commit:
 ACPI: processor: call _PDC early
 78f1699659963fff97975df44db6d5dbe7218e55

But this results in a section mismatch:

WARNING: drivers/acpi/acpi.o(.text+0xa9c1): Section mismatch in reference from the
function acpi_early_processor_set_pdc() to the variable .cpuinit.data:processor_idle_dmi_table
The function acpi_early_processor_set_pdc() references
the variable __cpuinitdata processor_idle_dmi_table.
This is often because acpi_early_processor_set_pdc lacks a __cpuinitdata
annotation or the annotation of processor_idle_dmi_table is wrong.

The only caller of acpi_early_processor_set_pdc() is acpi_bus_init() which
is an "__init" function. So the correct fix here is to mark
acpi_early_processor_set_pdc() "__init" too.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-16 02:00:44 -05:00
070a24f4d2 ACPI: Remove unnecessary cast.
The struct seq_file 'private' member is a void *, the cast is not needed.
Also, remove an extra whitespace line.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 23:06:44 -05:00
6a4e2b7503 ACPI: Advertise to BIOS in _OSC: _OST on _PPC changes
If the BIOS pokes the system-wide OSC bits to see if Linux
supports evaluating _OST after a _PPC change notification,
answer yes.

Also, fix an oversight where we neglected to set the OSC
bit advertising processor aggregator device support
when acpi-pad is compiled as a module.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 23:05:00 -05:00
54070101f8 ACPI: EC: Add wait for irq storm
Merge of poll and irq modes accelerated EC transaction, so
that keyboard starts to suffer again. Add msleep(1) into
transaction path for the storm to allow keyboard controller
to do its job.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=14747

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 22:53:04 -05:00
f5347867c5 ACPI: SBS: Move SBS HC callback to faster Notify queue
SBS transactions should happen in Notify work queue, to not create
a dead lock with GPE execution accessing SBS devices.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 22:52:48 -05:00
c67fcd670b ACPI: Battery: Add support for _BIX extended info method
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 17:03:33 -05:00
16698857fb ACPI: SBS: Export cycle_count
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 16:59:50 -05:00
7b3bcc4a1a ACPI: Battery: Add bit flags
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-01-15 16:55:51 -05:00
0f1d683fb3 [CPUFREQ] Processor Clocking Control interface driver
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>
2010-01-13 10:55:16 -05:00
c504f8cb68 ACPI video: Prune dupe video devices, unless "video.allow_duplicates"
Some buggy BIOS exports multiple ACPI video bus devices for the same
VGA controller, and multiple backlight control methods as well.
This messes up the ACPI video backlight control.

http://bugzilla.kernel.org/show_bug.cgi?id=13577

With this patch applied, only the FIRST ACPI video bus device
under a PCI device node is bind to ACPI video driver by default.

If the first ACPI video bus device doesn't work well, we can use
video.allow_duplicates=1 to go back to the old behavior.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2009-12-30 20:30:04 -05:00