linux-stable.git/include/acpi/processor.h, branch linux-2.6.33.y Linux kernel stable tree ACPI: skip checking BM_STS if the BIOS doesn't ask for it 2010-08-02T17:26:45+00:00 Len Brown len.brown@intel.com 2010-07-22T20:54:27+00:00 75676db2d5fe83904ca91c6c40ac81aad54b6493 commit 718be4aaf3613cf7c2d097f925abc3d3553c0605 upstream. It turns out that there is a bit in the _CST for Intel FFH C3 that tells the OS if we should be checking BM_STS or not. Linux has been unconditionally checking BM_STS. If the chip-set is configured to enable BM_STS, it can retard or completely prevent entry into deep C-states -- as illustrated by turbostat: http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/ ref: Intel Processor Vendor-Specific ACPI Interface Specification table 4 "_CST FFH GAS Field Encoding" Bit 1: Set to 1 if OSPM should use Bus Master avoidance for this C-state https://bugzilla.kernel.org/show_bug.cgi?id=15886 Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
commit 718be4aaf3613cf7c2d097f925abc3d3553c0605 upstream.

It turns out that there is a bit in the _CST for Intel FFH C3
that tells the OS if we should be checking BM_STS or not.

Linux has been unconditionally checking BM_STS.
If the chip-set is configured to enable BM_STS,
it can retard or completely prevent entry into
deep C-states -- as illustrated by turbostat:

http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/

ref: Intel Processor Vendor-Specific ACPI Interface Specification
table 4 "_CST FFH GAS Field Encoding"
Bit 1: Set to 1 if OSPM should use Bus Master avoidance for this C-state

https://bugzilla.kernel.org/show_bug.cgi?id=15886

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
ACPI: processor: remove _PDC object list from struct acpi_processor 2009-12-22T08:35:16+00:00 Alex Chiang achiang@hp.com 2009-12-20T19:23:21+00:00 e59897fe443b5b0a71e135ef4020d1937c9f8901 When we call _PDC, we get a handle to the processor, allocate the object list buffer as needed, and free it immediately after calling _PDC. There's no need to drag around this object list with us everywhere else, so let's just get rid of it. Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Len Brown <len.brown@intel.com> 
When we call _PDC, we get a handle to the processor, allocate the
object list buffer as needed, and free it immediately after calling
_PDC.

There's no need to drag around this object list with us everywhere
else, so let's just get rid of it.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
ACPI: processor: change acpi_processor_set_pdc() interface 2009-12-22T08:33:58+00:00 Alex Chiang achiang@hp.com 2009-12-20T19:23:16+00:00 43bab25ced218385f7e6a076c2459ea008cfd2e1 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> 
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>
ACPI: processor: unify arch_acpi_processor_cleanup_pdc 2009-12-22T08:24:14+00:00 Alex Chiang achiang@hp.com 2009-12-20T19:19:34+00:00 47817254b8637b56730aec26eed2c337d3938bb5 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> 
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>
ACPI: processor: finish unifying arch_acpi_processor_init_pdc() 2009-12-22T08:24:13+00:00 Alex Chiang achiang@hp.com 2009-12-20T19:19:29+00:00 6c5807d7bc7d051fce00863ffb98d36325501eb2 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> 
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>
ACPI: processor: call _PDC early 2009-12-22T08:24:08+00:00 Alex Chiang achiang@hp.com 2009-12-20T19:19:09+00:00 78f1699659963fff97975df44db6d5dbe7218e55 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> 
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>
Merge branch 'ost' into release 2009-12-16T07:18:36+00:00 Len Brown len.brown@intel.com 2009-12-16T07:18:36+00:00 8fa79e08f50f4ec1fd8903eca6fd6f36c36dd4c4 Conflicts: include/acpi/processor.h Signed-off-by: Len Brown <len.brown@intel.com> 
Conflicts:
	include/acpi/processor.h

Signed-off-by: Len Brown <len.brown@intel.com>
[ACPI/CPUFREQ] Introduce bios_limit per cpu cpufreq sysfs interface 2009-11-24T18:33:34+00:00 Thomas Renninger trenn@suse.de 2009-11-19T11:31:01+00:00 e2f74f355e9e2914483db10c05d70e69e0b7ae04 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> 
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>
ACPI: Notify the _PPC evaluation status to the platform 2009-11-06T06:58:07+00:00 Zhao Yakui yakui.zhao@intel.com 2009-10-16T01:20:41+00:00 d81c45e1c9369855901420f79114852eba2ea16a According to the ACPI spec(section 8.4.4.3) OSPM should convey the _PPC evaluations status to the platform if there exists the _OST object. The _OST contains two arguments: The first is the PERFORMANCE notificatin event. The second is the status of _PPC object. OSPM will convey the _PPC evaluation status to the platform. Of course when the module parameter of "ignore_ppc" is added, OSPM won't evaluate the _PPC object. But it will call the _OST object. At the same time the _OST object will be evaluated only when the PERFORMANCE notification event is received. Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> 
According to the ACPI spec(section 8.4.4.3) OSPM should convey the _PPC
evaluations status to the platform if there exists the _OST object.
The _OST contains two arguments:
	The first is the PERFORMANCE notificatin event.
	The second is the status of _PPC object.
OSPM will convey the _PPC evaluation status to the platform.
Of course when the module parameter of "ignore_ppc" is added, OSPM won't
evaluate the _PPC object. But it will call the _OST object.

At the same time the _OST object will be evaluated only when the PERFORMANCE
notification event is received.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
ACPI processor: force throttling state when BIOS returns incorrect value 2009-08-27T03:06:53+00:00 Frans Pop elendil@planet.nl 2009-08-26T21:29:29+00:00 2a908002c7b1b666616103e9df2419b38d7c6f1f If the BIOS reports an invalid throttling state (which seems to be fairly common after system boot), a reset is done to state T0. Because of a check in acpi_processor_get_throttling_ptc(), the reset never actually gets executed, which results in the error reoccurring on every access of for example /proc/acpi/processor/CPU0/throttling. Add a 'force' option to acpi_processor_set_throttling() to ensure the reset really takes effect. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13389 This patch, together with the next one, fixes a regression introduced in 2.6.30, listed on the regression list. They have been available for 2.5 months now in bugzilla, but have not been picked up, despite various reminders and without any reason given. Google shows that numerous people are hitting this issue. The issue is in itself relatively minor, but the bug in the code is clear. The patches have been in all my kernels and today testing has shown that throttling works correctly with the patches applied when the system overheats (http://bugzilla.kernel.org/show_bug.cgi?id=13918#c14). Signed-off-by: Frans Pop <elendil@planet.nl> Acked-by: Zhang Rui <rui.zhang@intel.com> Cc: Len Brown <lenb@kernel.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
If the BIOS reports an invalid throttling state (which seems to be
fairly common after system boot), a reset is done to state T0.
Because of a check in acpi_processor_get_throttling_ptc(), the reset
never actually gets executed, which results in the error reoccurring
on every access of for example /proc/acpi/processor/CPU0/throttling.

Add a 'force' option to acpi_processor_set_throttling() to ensure
the reset really takes effect.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13389

This patch, together with the next one, fixes a regression introduced in
2.6.30, listed on the regression list. They have been available for 2.5
months now in bugzilla, but have not been picked up, despite various
reminders and without any reason given.

Google shows that numerous people are hitting this issue. The issue is in
itself relatively minor, but the bug in the code is clear.

The patches have been in all my kernels and today testing has shown that
throttling works correctly with the patches applied when the system
overheats (http://bugzilla.kernel.org/show_bug.cgi?id=13918#c14).

Signed-off-by: Frans Pop <elendil@planet.nl>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>