Commit Graph

472 Commits

Author SHA1 Message Date
Henrique de Moraes Holschuh
e0298997ac ACPI: ibm-acpi: add support for the ultrabay on the T60,X60
This patch adds support for the ultrabay on the T60, X60 and other new
ThinkPads that have a SATA ultrabay.

I intend to keep bay and dock support in ibm-acpi working and updated until
it finally gets deprecated and removed in favour of the generic dock and
bay support.  But we aren't there yet.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:45 -05:00
Henrique de Moraes Holschuh
16663a87ad ACPI: ibm-acpi: implement fan watchdog command
This patch implements a fan control safety watchdog, by request of the
authors of userspace fan control scripts.

When the watchdog timer expires, the equivalent action of a "fan enable"
command is executed.  The watchdog timer is reset at every reception of a
fan control command that could change the state of the fan itself.

This command is meant to be used by userspace fan control daemons, to make
sure the fan is never left set to an unsafe level because of userspace
problems.

Users of the X31/X40/X41 "speed" command are on their own, the current
implementation of "speed" is just too incomplete to be used safely,
anyway.  Better to never use it, and just use the "level" command instead.

The watchdog is programmed using echo "watchdog <number>" > fan, where
number is the number of seconds to wait before doing an "enable", and zero
disables the watchdog.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:44 -05:00
Henrique de Moraes Holschuh
778b4d742b ACPI: ibm-acpi: workaround for EC 0x2f initialization bug
A few ThinkPads fail to initialize EC register 0x2f both in the EC
firmware and ACPI DSDT.  If the BIOS and the ACPI DSDT also do not
initialize it, then the initial status of that register does not
correspond to reality.

On all reported buggy machines, EC 0x2f will read 0x07 (fan level 7) upon
cold boot, when the EC is actually in mode 0x80 (auto mode).  Since
returning a text string ("unknown") would break a number of userspace
programs, instead we correct the reading for the most probably correct
answer, and return it is in auto mode.

The workaround flags the status and level as unknown on module load/kernel
boot, until we are certain at least one fan control command was issued,
either by us, or by something else.

We don't work around the bug by doing a "fan enable" at module
load/startup (which would initialize the EC register) because it is not
known if these ThinkPad ACPI DSDT might have set the fan to level 7
instead of "auto" (we don't know if they can do this or not) due to a
thermal condition, and we don't want to override that, should they be
capable of it.

We should be setting the workaround flag to "status known" upon resume, as
both reports and a exaustive search on the DSDT tables at acpi.sf.net show
that the DSDTs always enable the fan on resume, thus working around the
bug.  But since we don't have suspend/resume handlers in ibm-acpi yet and
the "EC register 0x2f was modified" logic is likely to catch the change
anyway, we don't.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:44 -05:00
Henrique de Moraes Holschuh
49a13cd6a2 ACPI: ibm-acpi: store embedded controller firmware version for matching
This patch changes the ThinkPad Embedded Controller DMI matching
code to store the firmware version of the EC for later usage, e.g.
for quirks.

It also prints the firmware version when starting up.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:44 -05:00
Henrique de Moraes Holschuh
a12095c2b5 ACPI: ibm-acpi: fix and extend fan control functions
This patch extend fan control functions, implementing enable/disable for
all write access modes, implementing level control for all level-capable
write access modes.

The patch also updates the documentation, explaining levels auto and
disengaged.

ABI changes:
	1. Support level 0 as an equivalent to disable
	2. Add support for level auto and level disengaged when doing
	   EC 0x2f fan control
	3. Support enable/disable for all level-based write access modes
	4. Add support for level command on FANS thinkpads, as per
	   thinkwiki reports

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:43 -05:00
Henrique de Moraes Holschuh
1c6a334e9c ACPI: ibm-acpi: fix and extend fan enable
This patch fix fan enable to attempt to do the right thing and not slow
down the fan if it is forced to the maximum speed.  It also extends fan
enable to work on older thinkpads.

ABI changes:
	1.  Support enable/disable for all level-based write access modes

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:40 -05:00
Henrique de Moraes Holschuh
bab812a329 ACPI: ibm-acpi: extend fan status functions
This patch fixes fan_read to return correct values for all fan access
modes.  It also implements some fan access mode status output that was
missing, and normalizes the proc fan abi to return consistent data across
all fan read/write modes.

Userspace ABI changes and extensions:
	1. Return status: enable/disable for *all* modes
	   (this actually improves compatibility with userspace utils!)
	2. Return level: auto and level: disengaged for EC 2f access mode
	3. Return level: <number> for EC 0x2f access mode
	4. Return level 0 as well as "disabled" in level-aware modes

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:40 -05:00
Henrique de Moraes Holschuh
a8b7a6626d ACPI: ibm-acpi: document fan control
This patch documents the ThinkPad fan control strategies.  Source of the
data:

0. ibm-acpi source
1. DSDTs for various ThinkPads (770, X31, X40, X41, T43, A21m, T22)
2. http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Firmware_Issues
3. http://thinkwiki.org/wiki/How_to_control_fan_speed
4. Various threads about windows fan control utilities in thinkpads.com

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:40 -05:00
Henrique de Moraes Holschuh
18ad7996e1 ACPI: ibm-acpi: cleanup fan_write
This patch cleans up fan_write so that it is much easier to read and
extend.  It separates the proc api handling from the operations themselves.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:39 -05:00
Henrique de Moraes Holschuh
c52f0aa574 ACPI: ibm-acpi: break fan_read into separate functions
This patch breaks fan_read mechanics into a generic function to get fan
status and speed, and leaves only the procfs interface code in fan_read.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:39 -05:00
Henrique de Moraes Holschuh
3ef8a6096c ACPI: ibm-acpi: clean up fan_read
This patch cleans up fan_read so that it is much easier to read and
extend.

The patch fixes the userspace ABI to return "status: not supported" (like
all other ibm-acpi functions) when neither fan status or fan control are
possible.

It also fixes the userspace ABI to return EIO if ACPI access to the EC
fails, instead of returning "status: unreadable" or "speed: unreadable".

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:39 -05:00
Henrique de Moraes Holschuh
69ba91cbd6 ACPI: ibm-acpi: prepare to cleanup fan_read and fan_write
This patch lays some groundwork for a fan_read and fan_write cleanup in the
next patches.  To do so, it provides a new fan_init initializer, and also some
constants (through enums).

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:39 -05:00
Henrique de Moraes Holschuh
60eb0b35a9 ACPI: ibm-acpi: Implement direct-ec-access thermal reading modes for up to 16 sensors
This patch extends ibm-acpi to support reading thermal sensors directly
through ACPI EC register access.  It uses a DMI match to detect ThinkPads
with a new-style embedded controller, that are known to have forward-
compatible register maps and use 0x00 to fill in non-used registers and
export thermal sensors at EC offsets 0x78-7F and 0xC0-C7.

Direct ACPI EC register access is implemented for 8-sensor and 16-sensor
new-style ThinkPad controller firmwares as an experimental feature.  The
code does some limited sanity checks on the temperatures read through EC
access, and will default to the old ACPI TMP0-7 mode if anything is amiss.

Userspace ABI is not changed for 8 sensors, but /proc/acpi/ibm/thermal is
extended for 16 sensors if the firmware supports 16 sensors.

A documentation update is also provided.

The information about the ThinkPad register map was determined by studying
ibm-acpi "ecdump" output from various ThinkPad models, submitted by
subscribers of the linux-thinkpad mailinglist.  Futher information was
gathered from the DSDT tables, as they describe the EC register map in
recent ThinkPads.

DSDT source shows that TMP0-7 access and direct register access are
actually the same thing on these firmwares, but unfortunately IBM never
did update their DSDT EC register map to export TMP8-TMP15 for the second
range of sensors.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:38 -05:00
Henrique de Moraes Holschuh
a26f878abc ACPI: ibm-acpi: Use a enum to select the thermal sensor reading strategy
This patch consolidades all decisions regarding the strategy to be used to
read thinkpad thermal sensors into a single enum, and refactors the
thermal sensor reading code to use a much more readable (and easier to
extend) switch() construct, in a separate function.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:38 -05:00
Henrique de Moraes Holschuh
8d29726434 ACPI: ibm-acpi: trivial Lindent cleanups
This patch just makes drives/acpi/ibm-acpi.c Lindent-clean, as requested by
Len Brown.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:34 -05:00
Henrique de Moraes Holschuh
3dfd35cd21 ACPI: ibm-acpi: do not use / in driver names
ibm-acpi uses sub-device names like ibm/hotkey, which get in the way of
a sysfs conversion.  Fix it to use ibm_hotkey instead.  Thanks to Zhang
Rui for noticing this.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
2006-12-07 01:38:31 -05:00
Holger Macht
c926355724 ACPI: toshiba_acpi: Add support for the generic backlight device
Add support for the generic backlight interface below /sys/class/backlight.
Keep the procfs brightness handling for backward compatibility.

To achive this, add two generic functions get_lcd and set_lcd
to be used both by the procfs related and the sysfs related methods.

[apw@shadowen.org: backlight users need to select BACKLIGHT_CLASS_DEVICE]

Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-21 01:37:28 -04:00
Holger Macht
2039a6eb72 ACPI: asus_acpi: Add support for the generic backlight device
Add support for the generic backlight interface below /sys/class/backlight.
Keep the procfs brightness handling for backward compatibility.

[apw@shadowen.org: backlight users need to select BACKLIGHT_CLASS_DEVICE]

Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-21 01:36:00 -04:00
Holger Macht
8acb025085 ACPI: ibm_acpi: Add support for the generic backlight device
Add support for the generic backlight interface below /sys/class/backlight.
The patch keeps the procfs brightness handling for backward compatibility.

Add two generic functions brightness_get and brightness_set
to be used both by the procfs related and the sysfs related methods.

[apw@shadowen.org: backlight users need to select BACKLIGHT_CLASS_DEVICE]

Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-21 01:34:48 -04:00
Yasunori Goto
887b95931b [PATCH] acpi memory hotplug: remove strange add_memory fail message
I wrote a patch to avoid redundant memory hot-add call at boot time.  This
was cause of strange fail message of memory hotplug like "ACPI: add_memory
failed".  Memory is recognized by early boot code with EFI/E820.

But, if DSDT describes memory devices for them, then hot-add code is called
for already recognized memory, and it shows fail messages with -EEXIST.
So, sys admin will misunderstand this message as something wrong by it.

This patch avoids them by preventing redundant hot-add call until
completion of driver initialization.

[akpm@osdl.org: cleanups]
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:38 -07:00
Yasunori Goto
6cbe44cd8d [PATCH] Change log level of a message of acpi_memhotplug to KERN_DEBUG
I suppose this message seems quite useless except debugging.  It just shows
"Hotplug Mem Device".  System admin can't know anything by this message.
So, I would like to change it to KERN_DEBUG.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:37 -07:00
Darrick J. Wong
c5a114f1fb [PATCH] fix "ACPI: Processor native C-states using MWAIT"
This patch breaks C-state discovery on my IBM IntelliStation Z30 because
the return value of acpi_processor_get_power_info_fadt is not assigned to
"result" in the case that acpi_processor_get_power_info_cst returns
-ENODEV.  Thus, if ACPI provides C-state data via the FADT and not _CST (as
is the case on this machine), we incorrectly exit the function with -ENODEV
after reading the FADT.  The attached patch sets the value of result so
that we don't exit early.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Acked-by: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-20 10:26:37 -07:00
Andrew Morton
1fec74a9cd [PATCH] acpi_processor_latency_notifier(): UP warning fix
drivers/acpi/processor_idle.c:1112: warning: 'smp_callback' defined but not used

Cc: Len Brown <lenb@kernel.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-17 08:18:44 -07:00
Len Brown
9aaed2b42d Pull trivial into test branch 2006-10-14 02:28:07 -04:00
Len Brown
384bc8f070 Pull bugzilla-5534 into test branch 2006-10-14 02:26:42 -04:00
Len Brown
ed3269a31b Pull ec into test branch 2006-10-14 02:26:10 -04:00
Len Brown
d7321ad293 Pull mwait into test branch 2006-10-14 02:25:59 -04:00
Len Brown
1d5b30fc33 Pull battery into test branch 2006-10-14 02:25:48 -04:00
Len Brown
c92fd49c54 Pull ibm into test branch 2006-10-14 02:25:40 -04:00
Len Brown
9443d7c934 Pull asus into test branch 2006-10-14 02:25:33 -04:00
Jiri Kosina
34c4415ab8 ACPI: check battery status on resume for un/plug events during sleep
Add ->resume method to the ACPI battery handler to check
if the battery state has changed during sleep.
If yes, update the ACPI internal data structures
for benefit of /proc/acpi/battery/.

Signed-off-by: Jiri Kosina <jikos@jikos.cz>
Cc: Stefan Seyfried <seife@suse.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 02:22:51 -04:00
Eiichiro Oiwa
aeb1104814 ACPICA: Fix incorrect handling of PCI Express Root Bridge _HID
I could not get correct PCI Express bus number from the structure of
acpi_object_extra. I always get zero as bus number regardless of bus
location. I found that there is incorrect comparison with _HID (PNP0A08) in
acpi/events/evrgnini.c and PCI Express _BBN method always fail.
Therefore, we always get zero as PCI Express bus number.
http://bugzilla.kernel.org/show_bug.cgi?id=7145

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 02:13:38 -04:00
Alexey Dobriyan
6df05702f9 ACPI: asus_acpi: don't printk on writing garbage to proc files
This reporting is useless (we errno anyway).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 02:03:49 -04:00
Darren Jenkins
6311f0dac0 ACPI: asus_acpi: fix proc files parsing
ICC complains about a "Pointless comparsion of unsigned interger with zero"
@ line 760 & 808 of asus_acpi.c

parse_arg() mentioned below returns -E but it's copied into unsigned variable...

Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 02:03:02 -04:00
Randy Dunlap
a790b323fb ACPI: fix printk format warnings
Fix printk format warnings in drivers/acpi:
drivers/acpi/tables/tbget.c:326: warning: format '%X' expects type 'unsigned int', but argument 5 has type 'long unsigned int'
drivers/acpi/tables/tbrsdt.c:189: warning: format '%X' expects type 'unsigned int', but argument 5 has type 'long unsigned int'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:59:46 -04:00
Pierre Ossman
7af8b66004 ACPI: fix section for CPU init functions
The ACPI processor init functions should be marked as __cpuinit as they use
structures marked with __cpuinitdata.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:58:38 -04:00
Len Brown
f4d2e2d87e ACPI: update comments in motherboard.c
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:56:27 -04:00
Jiri Kosina
168a328f30 ACPI: acpi_pci_link_set() can allocate with either GFP_ATOMIC or GFP_KERNEL
acpi_pci_link_set() allocates both with interrupts on
and with interrupts off (resume-time), so check interrupts
and decide on GFP_ATOMIC or GFP_KERNEL at run-time.

Signed-off-by: Jiri Kosina <jikos@jikos.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:54:21 -04:00
Dmitry Torokhov
786f18c666 ACPI: fix potential OOPS in power driver with CONFIG_ACPI_DEBUG
device was set to null and used before set in a debug printk

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:54:21 -04:00
Alexey Y. Starikovskiy
37605a6900 ACPI: created a dedicated workqueue for notify() execution
http://bugzilla.kernel.org/show_bug.cgi?id=5534#c160

Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:50:10 -04:00
Alexey Y. Starikovskiy
fcfc638c6b ACPI: Remove deferred execution from global lock acquire wakeup path
On acquiring the ACPI global lock, if there were sleepers on the lock,
we used to use acpi_os_execute() to defer a thread which would signal
sleepers.  Now just signal the semaphore directly.

http://bugzilla.kernel.org/show_bug.cgi?id=5534#c159

Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 01:50:09 -04:00
Lennart Poettering
ab9e43c640 ACPI: EC: export ec_transaction() for msi-laptop driver
Signed-off-by: Lennart Poettering <mzxreary@0pointer.de>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:56 -04:00
Denis M. Sadykov
6ffb221a82 ACPI: EC: Simplify acpi_hw_low_level*() with inb()/outb().
Simplify acpi_hw_low_level_xxx() functions to inb() and outb().

Signed-off-by: Alexey Y. Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:56 -04:00
Denis M. Sadykov
8e0341ba79 ACPI: EC: Unify poll and interrupt gpe handlers
Signed-off-by: Alexey Y. Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:55 -04:00
Denis M. Sadykov
3576cf619b ACPI: EC: Unify poll and interrupt mode transaction functions
Signed-off-by: Alexey Y. Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:55 -04:00
Denis M. Sadykov
703959d47e ACPI: EC: Remove unused variables and duplicated code
Signed-off-by: Alexey Y. Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:54 -04:00
Denis M. Sadykov
7c6db5e512 ACPI: EC: Remove unnecessary delay added by previous transation patch.
Remove unnecessary delay (50 ms) while reading data from EC in interrupt mode.

Signed-off-by: Alexey Y. Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:53 -04:00
Lennart Poettering
d7a76e4cb3 ACPI: consolidate functions in acpi ec driver
Unify the following functions:

    acpi_ec_poll_read()
    acpi_ec_poll_write()
    acpi_ec_poll_query()
    acpi_ec_intr_read()
    acpi_ec_intr_write()
    acpi_ec_intr_query()

into:

    acpi_ec_poll_transaction()
    acpi_ec_intr_transaction()

These new functions take as arguments an ACPI EC command, a few bytes
to write to the EC data register and a buffer for a few bytes to read
from the EC data register. The old _read(), _write(), _query() are
just special cases of these functions.

Then unified the code in acpi_ec_poll_transaction() and
acpi_ec_intr_transaction() a little more. Both functions are now just
wrappers around the new acpi_ec_transaction_unlocked() function. The
latter contains the EC access logic, the two original
function now just do their special way of locking and call the the
new function for the actual work.

This saves a lot of very similar code. The primary reason for doing
this, however, is that my driver for MSI 270 laptops needs to issue
some non-standard EC commands in a safe way. Due to this I added a new
exported function similar to ec_write()/ec_write() which is called
ec_transaction() and is essentially just a wrapper around
acpi_ec_{poll,intr}_transaction().

Signed-off-by: Lennart Poettering <mzxreary@0pointer.de>
Acked-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:49:52 -04:00
Venkatesh Pallipadi
991528d734 ACPI: Processor native C-states using MWAIT
Intel processors starting with the Core Duo support
support processor native C-state using the MWAIT instruction.
Refer: Intel Architecture Software Developer's Manual
http://www.intel.com/design/Pentium4/manuals/253668.htm

Platform firmware exports the support for Native C-state to OS using
ACPI _PDC and _CST methods.
Refer: Intel Processor Vendor-Specific ACPI: Interface Specification
http://www.intel.com/technology/iapc/acpi/downloads/302223.htm

With Processor Native C-state, we use 'MWAIT' instruction on the processor
to enter different C-states (C1, C2, C3).  We won't use the special IO
ports to enter C-state and no SMM mode etc required to enter C-state.
Overall this will mean better C-state support.

One major advantage of using MWAIT for all C-states is, with this and
"treat interrupt as break event" feature of MWAIT, we can now get accurate
timing for the time spent in C1, C2, ..  states.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:35:39 -04:00
Lebedev, Vladimir P
3cd5b87d96 ACPI: sbs: fix module_param() initializers
Signed-off-by: Len Brown <len.brown@intel.com>
2006-10-14 00:34:00 -04:00