History log of /linux-master/drivers/acpi/processor_pdc.c
Revision Date Author Comments
# b2eb3e67 14-Sep-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Fix uninitialized access of buf in acpi_set_pdc_bits()

A bug was introduced during unification of setting CAP_SMP_T_SWCOORD for
the _PDC and _OSC methods.

The third u32 in the buffer is never cleared before setting bits on it.
The memory is not guaranteed to be zero as it was allocated by kmalloc()
instead of kzalloc().

Fix this by initializing the third u32 in the buffer to 0.

Fixes: b9e8d0168a7a ("ACPI: processor: Set CAP_SMP_T_SWCOORD in arch_acpi_set_proc_cap_bits()")
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# b9e8d016 10-Jul-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Set CAP_SMP_T_SWCOORD in arch_acpi_set_proc_cap_bits()

Currently, ACPI_PROC_CAP_SMP_T_SWCOORD is set in acpi_set_pdc_bits(), but
it is not _PDC-specific. It should be set along with the other processor
capability bits.

Move the setting of ACPI_PROC_CAP_SMP_T_SWCOORD to
arch_acpi_set_proc_cap_bits().

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# 4f37ab5e 10-Jul-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Clear C_C2C3_FFH and C_C1_FFH in arch_acpi_set_proc_cap_bits()

Currently arch_acpi_set_proc_cap_bits() clears ACPI_PDC_C_C2C3_FFH bit in
case MWAIT instruction is not supported.

It should also clear ACPI_PDC_C_C1_FFH, as when MWAIT is not supported,
C1 is entered by executing the HLT instruction.

Quote from the C_C1_FFH description:

"If set, OSPM is capable of performing native C State instructions (beyond
halt) for the C1 handler in multi-processor configurations". As without
MWAIT there is no native C-state instructions beyond HALT, this bit
should be toggled off."

Clear ACPI_PDC_C_C1_FFH and ACPI_PDC_C_C2C3_FFH in
arch_acpi_set_proc_cap_bits() in case MWAIT is not supported or
overridden.

Remove setting those bits from the processor_pdc.c code.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# c9e6c5e6 10-Jul-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Rename ACPI_PDC symbols

The prefix in the names of the ACPI_PDC symbols suggests that they are
only relevant for _PDC, but in fact they can also be used in the _OSC.

Change that prefix to a more generic ACPI_PROC_CAP that will better
reflect the purpose of those symbols as they represent bits in a general
processor capabilities buffer.

Rename pdc_intel.h to proc_cap_intel.h to follow the change of the
symbol name prefix.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# c5e4d05d 10-Jul-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Refactor arch_acpi_set_pdc_bits()

The capabilities buffer modified by the arch_acpi_set_pdc_bits() is not
_PDC-specific, as it can be used by _OSC too.

Change the name of that function to better reflect its independence from
_PDC and make it take the capabilities buffer address as the argument
directly, without any offset, as _OSC and _PDC use different capabilities
buffer offsets.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# 3272a4aa 10-Jul-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Move processor_physically_present() to acpi_processor.c

Since _PDC method is deprecated and a preferred method of communicating
OSPM processor power management capabilities is _OSC, there is a need to
move function checking whether processor is present as this logic is not
_PDC specific.

Move processor_physically_present() to acpi_processor.c.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# 0a0e2ea6 10-Jul-2023 Michal Wilczynski <michal.wilczynski@intel.com>

ACPI: processor: Move MWAIT quirk out of acpi_processor.c

Commit 2a2a64714d9c ("ACPI: Disable MWAIT via DMI on broken Compal board")
introduced a workaround for MWAIT for a specific x86 system.

Move the code outside of acpi_processor.c to acpi/x86/ directory for
consistency and rename the functions associated with it, so their names
start with "acpi_proc_quirk_" to make the goal obvious.

No intentional functional impact.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
[ rjw: Subject and changelog edits, two function names changed ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# 073828e9 21-Mar-2023 Roger Pau Monne <roger.pau@citrix.com>

ACPI: processor: Fix evaluating _PDC method when running as Xen dom0

In ACPI systems, the OS can direct power management, as opposed to the
firmware. This OS-directed Power Management is called OSPM. Part of
telling the firmware that the OS going to direct power management is
making ACPI "_PDC" (Processor Driver Capabilities) calls. These _PDC
methods must be evaluated for every processor object. If these _PDC
calls are not completed for every processor it can lead to
inconsistency and later failures in things like the CPU frequency
driver.

In a Xen system, the dom0 kernel is responsible for system-wide power
management. The dom0 kernel is in charge of OSPM. However, the
number of CPUs available to dom0 can be different than the number of
CPUs physically present on the system.

This leads to a problem: the dom0 kernel needs to evaluate _PDC for
all the processors, but it can't always see them.

In dom0 kernels, ignore the existing ACPI method for determining if a
processor is physically present because it might not be accurate.
Instead, ask the hypervisor for this information.

Fix this by introducing a custom function to use when running as Xen
dom0 in order to check whether a processor object matches a CPU that's
online. Such checking is done using the existing information fetched
by the Xen pCPU subsystem, extending it to also store the ACPI ID.

This ensures that _PDC method gets evaluated for all physically online
CPUs, regardless of the number of CPUs made available to dom0.

Fixes: 5d554a7bb064 ("ACPI: processor: add internal processor_physically_present()")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# 52af99c3 22-Feb-2021 Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: processor: Get rid of ACPICA message printing

The ACPI_DEBUG_PRINT() and ACPI_EXCEPTION() macros are used for
message printing in the ACPICA code and they should not be used
elsewhere. Special configuration (either kernel command line or
sysfs-based) is needed to see the messages printed by them and
the format of those messages is also special and convoluted.

For this reason, replace all of the ACPI_DEBUG_PRINT() and
ACPI_EXCEPTION() instances in the ACPI processor driver with
corresponding dev_*(), acpi_handle_*() and pr_*() calls depending
on the context in which they appear.

Also drop the ACPI_PROCESSOR_COMPONENT definition that is not going
to be necessary any more.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>


# b2441318 01-Nov-2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 6faadbbb 14-Sep-2017 Christoph Hellwig <hch@lst.de>

dmi: Mark all struct dmi_system_id instances const

... and __initconst if applicable.

Based on similar work for an older kernel in the Grsecurity patch.

[JD: fix toshiba-wmi build]
[JD: add htcpen]
[JD: move __initconst where checkscript wants it]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jean Delvare <jdelvare@suse.de>


# 25956b66 10-May-2015 Hanjun Guo <guohanjun@huawei.com>

ACPI / processor: Introduce invalid_logical_cpuid()

In ACPI processor drivers, we use direct comparisons of cpu logical
id with -1 which are error prone in case logical cpuid is accidentally
assinged an error code and prevents us from returning an error-encoding
cpuid directly in some cases.

So introduce invalid_logical_cpuid() to identify cpu with invalid
logical cpu num, then it will be used to replace the direct comparisons
with -1.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# 46ba51ea 18-Jul-2014 Hanjun Guo <guohanjun@huawei.com>

ACPI / processor: Introduce ARCH_MIGHT_HAVE_ACPI_PDC

The use of _PDC is deprecated in ACPI 3.0 in favor of _OSC,
as ARM platform is supported only in ACPI 5.0 or higher version,
_PDC will not be used in ARM platform, so make Make _PDC only for
platforms with Intel CPUs.

Introduce ARCH_MIGHT_HAVE_ACPI_PDC and move _PDC related code in
ACPI processor driver into a single file processor_pdc.c, make x86
and ia64 select it when ACPI is enabled.

This patch also use pr_* to replace printk to fix the checkpatch
warning and factor acpi_processor_alloc_pdc() a little bit to
avoid duplicate pr_err() code.

Suggested-by: Robert Richter <rric@kernel.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>


# a4932299 20-Jan-2010 Alex Chiang <achiang@hp.com>

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>


# 0406ad33 20-Jan-2010 Alex Chiang <achiang@hp.com>

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>


# 2205cbe8 19-Jan-2010 Alex Chiang <achiang@hp.com>

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>


# 7a0b73a4 28-Dec-2009 Tony Luck <tony.luck@intel.com>

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>


# 43bab25c 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: change acpi_processor_set_pdc() interface

When calling _PDC, we really only need the handle to the processor
to call the method; we don't look at any other parts of the
struct acpi_processor * given to us.

In the early path, when we walk the namespace, we are given the
handle directly, so just pass it through to acpi_processor_set_pdc()
without stuffing it into a wasteful struct acpi_processor allocated
on the stack each time

This saves 2834 bytes of stack.

Update the interface accordingly.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# b9c2db78 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: open code acpi_processor_cleanup_pdc

We have the acpi_object_list * right there in acpi_processor_set_pdc()
so it doesn't seem necessary for an entire helper function just to
free it.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# fa118564 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: change acpi_processor_eval_pdc interface

acpi_processor_eval_pdc() really only needs a handle and an
acpi_object_list * to do its work.

No need to pass in a struct acpi_processor *, so let's be more specific
about what we want.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 3b407aef 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: introduce acpi_processor_alloc_pdc()

acpi_processor_init_pdc() isn't really doing anything interesting
with the struct acpi_processor * parameter. Its real job is to allocate
the buffer for the _PDC bits.

So rename the function to acpi_processor_alloc_pdc(), and just return
the struct acpi_object_list * it's supposed to allocate.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 47817254 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: unify arch_acpi_processor_cleanup_pdc

The x86 and ia64 implementations of the function in $subject are
exactly the same.

Also, since the arch-specific implementations of setting _PDC have
been completely hollowed out, remove the empty shells.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 6c5807d7 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: finish unifying arch_acpi_processor_init_pdc()

The only thing arch-specific about calling _PDC is what bits get
set in the input obj_list buffer.

There's no need for several levels of indirection to twiddle those
bits. Additionally, since we're just messing around with a buffer,
we can simplify the interface; no need to pass around the entire
struct acpi_processor * just to get at the buffer.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 08ea48a3 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: factor out common _PDC settings

Both x86 and ia64 initialize _PDC with mostly common bit settings.

Factor out the common settings and leave the arch-specific ones alone.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 407cd87c 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: unify arch_acpi_processor_init_pdc

The x86 and ia64 implementations of arch_acpi_processor_init_pdc()
are almost exactly the same. The only difference is in what bits
they set in obj_list buffer.

Combine the boilerplate memory management code, and leave the
arch-specific bit twiddling in separate implementations.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 1d9cb470 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: introduce arch_has_acpi_pdc

arch dependent helper function that tells us if we should attempt to
evaluate _PDC on this machine or not.

The x86 implementation assumes that the CPUs in the machine must be
homogeneous, and that you cannot mix CPUs of different vendors.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>


# 78f16996 20-Dec-2009 Alex Chiang <achiang@hp.com>

ACPI: processor: call _PDC early

We discovered that at least one machine (HP Envy), methods in the DSDT
attempt to call external methods defined in a dynamically loaded SSDT.

Unfortunately, the DSDT methods we are trying to call are part of the
EC initialization, which happens very early, and the the dynamic SSDT
is only loaded when a processor _PDC method runs much later.

This results in namespace lookup errors for the (as of yet) undefined
methods.

Since Windows doesn't have any issues with this machine, we take it
as a hint that they must be evaluating _PDC much earlier than we are.

Thus, the proper thing for Linux to do should be to match the Windows
implementation more closely.

Provide a mechanism to call _PDC before we enable the EC. Doing so loads
the dynamic tables, and allows the EC to be enabled correctly.

The ACPI processor driver will still evaluate _PDC in its .add() method
to cover the hotplug case.

Resolves: http://bugzilla.kernel.org/show_bug.cgi?id=14824

Cc: ming.m.lin@intel.com
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>