This reverts commit 281ea49b0c,
which broke ACPI Interrupt source overrides that move
the SCI from one IRQ in PIC mode to another in IOAPIC mode.
If the SCI shared an interrupt line with another device,
this would result in a "irq 18: nobody cared" type failure.
http://bugzilla.kernel.org/show_bug.cgi?id=7601
Signed-off-by: Len Brown <len.brown@intel.com>
Converts from using struct "class_device" to "struct device" making
everything show up properly in /sys/devices/ with symlinks from the
/sys/class directory.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Converts from using struct "class_device" to "struct device" making
everything show up properly in /sys/devices/ with symlinks from the
/sys/class directory.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch makes the needlessly global pci_bf_sort static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This updated patch adds the Intel ICH9 LPC and SMBus Controller DID's.
Signed-off-by: Jason Gaston <jason.d.gaston@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
ioremap must be balanced by an iounmap and failing to do so can result
in a memory leak.
Tested (compilation only):
- using allmodconfig
- making sure the files are compiling without any warning/error due to
new changes
Signed-off-by: Amol Lad <amol@verismonetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Mostly CodingStyle cleanups for arch/i386/pci/i386.c:
- fit in 80 columns;
- use a #defined value instead of an inline constant;
Also change one resource_size_t (DBG) printk from %08lx to %lx since
it can be more than 32 bits (more than 8 hexits).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The number of permutations of crap we do is amazing and almost all of it
has the wrong effect in 2.6.
At the heart of this is the PCI SFF magic which says that compatibility
mode PCI IDE controllers use ISA IRQ routing and hard coded addresses
not the BAR values. The old quirks variously clears them, sets them,
adjusts them and then IDE ignores the result.
In order to drive all this garbage out and to do it portably we need to
handle the SFF rules directly and properly. Because we know the device
BAR 0-3 are not used in compatibility mode we load them with the values
that are implied (and indeed which many controllers actually
thoughtfully put there in this mode anyway).
This removes special cases in the IDE layer and libata which now knows
that bar 0/1/2/3 always contain the correct address. It means our
resource allocation map is accurate from boot, not "mostly accurate"
after ide is loaded, and it shoots lots of code. There is also lots more
code and magic constant knowledge to shoot once this is in and settled.
Been in my test tree for a while both with drivers/ide and with libata.
Wants some -mm shakedown in case I've missed something dumb or there are
corner cases lurking.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When showing the stack backtrace, make sure that we never accept not
only an unchanging frame pointer, but also a frame pointer that moves
back down the stack frame. It must always grow up (toward older stack
frames).
I doubt this has triggered, but a subtly corrupt stack with extremely
unlucky contents could cause us to loop forever on a bogus endless frame
pointer chain.
This review was triggered by much worse problems happening in some of
the other stack unwinding code.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The scheduler on Andreas Friedrich's hyperthreading system stopped
working properly: the scheduler would never move tasks to another CPU!
The lask known working kernel was 2.6.8.
After a couple of attempts to corner the bug, the following smoking gun
was found:
BIOS reported wrong ACPI idfor the processor
CPU#1: set_cpus_allowed(), swapper:1, 3 -> 2
[<c0103bbe>] show_trace_log_lvl+0x34/0x4a
[<c0103ceb>] show_trace+0x2c/0x2e
[<c01045f8>] dump_stack+0x2b/0x2d
[<c0116a77>] set_cpus_allowed+0x52/0xec
[<c0101d86>] cpu_idle_wait+0x2e/0x100
[<c0259c57>] acpi_processor_power_exit+0x45/0x58
[<c0259752>] acpi_processor_remove+0x46/0xea
[<c025c6fb>] acpi_start_single_object+0x47/0x54
[<c025cee5>] acpi_bus_register_driver+0xa4/0xd3
[<c04ab2d7>] acpi_processor_init+0x57/0x77
[<c01004d7>] init+0x146/0x2fd
[<c0103a87>] kernel_thread_helper+0x7/0x10
a quick look at cpu_idle_wait() shows how broken that code is
on i386: it changes the init task's affinity map but never
restores it ...
and because all userspace tasks get forked by init, they all
inherited that single-CPU affinity mask. x86_64 cloned this
bug too.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Andreas Friedrich <andreas.friedrich@fujitsu-siemens.com>
Cc: Wolfgang Erig <Wolfgang.Erig@fujitsu-siemens.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Komuro reports that ISA interrupts do not work after a disable_irq(),
causing some PCMCIA drivers to not work, with messages like
eth0: Asix AX88190: io 0x300, irq 3, hw_addr xx:xx:xx:xx:xx:xx
eth0: found link beat
eth0: autonegotiation complete: 100baseT-FD selected
eth0: interrupt(s) dropped!
eth0: interrupt(s) dropped!
eth0: interrupt(s) dropped!
...
Linus Torvalds <torvalds@osdl.org> said:
"Now, edge-triggered interrupts are a _lot_ harder to mask, because the
Intel APIC is an unbelievable piece of sh*t, and has the edge-detect logic
_before_ the mask logic, so if a edge happens _while_ the device is
masked, you'll never ever see the edge ever again (unmasking will not
cause a new edge, so you simply lost the interrupt).
So when you "mask" an edge-triggered IRQ, you can't really mask it at all,
because if you did that, you'd lose it forever if the IRQ comes in while
you masked it. Instead, we're supposed to leave it active, and set a flag,
and IF the IRQ comes in, we just remember it, and mask it at that point
instead, and then on unmasking, we have to replay it by sending a
self-IPI."
This trivial patch solves the problem.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: Komuro <komurojun-mbn@nifty.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6:
[PATCH] x86-64: Fix race in exit_idle
[PATCH] x86-64: Fix vgetcpu when CONFIG_HOTPLUG_CPU is disabled
[PATCH] x86: Add acpi_user_timer_override option for Asus boards
[PATCH] x86-64: setup saved_max_pfn correctly (kdump)
[PATCH] x86-64: Handle reserve_bootmem_generic beyond end_pfn
[PATCH] x86-64: shorten the x86_64 boot setup GDT to what the comment says
[PATCH] x86-64: Fix PTRACE_[SG]ET_THREAD_AREA regression with ia32 emulation.
[PATCH] x86-64: Fix partial page check to ensure unusable memory is not being marked usable.
Revert "[PATCH] MMCONFIG and new Intel motherboards"
Fix interrupt routing for via 586 bridges. pirq can be 5 which needs to be
mapped to INTD. But currently the access functions can handle only pirq
1-4. this is similar to the other via chipsets where pirq 4 and 5 are both
mapped to INTD. Fixes bugzilla #7490
Cc: Daniel Paschka <monkey20181@gmx.net>
Cc: Adrian Bunk <bunk@susta.de>
Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Timer overrides are normally disabled on Nvidia board because
they are commonly wrong, except on new ones with HPET support.
Unfortunately there are quite some Asus boards around that
don't have HPET, but need a timer override.
We don't know yet how to handle this transparently,
but at least add a command line option to force the timer override
and let them boot.
Cc: len.brown@intel.com
Signed-off-by: Andi Kleen <ak@suse.de>
This refactoring actually optimizes the code a little by caching the value
that we think the device is programmed with instead of reading it back from
the hardware. Which simplifies the code a little and should speed things up a
bit.
This patch introduces the concept of a ht_irq_msg and modifies the
architecture read/write routines to update this code.
There is a minor consistency fix here as well as x86_64 forgot to initialize
the htirq as masked.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Acked-by: Bryan O'Sullivan <bos@pathscale.com>
Cc: <olson@pathscale.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are two bugs in the kretprobe-booster.
1) It doesn't make room for gs registers.
2) It doesn't change status of the current kprobe. This status will
effect the fault handling.
This patch fixes these bugs and, additionally, saves skipped registers for
compatibility with the original kretprobe.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
o Currently there is no specific alignment restriction in linker script
and in some cases it can be placed non 4K aligned addresses. This fails
kexec which checks that segment to be loaded is page aligned.
o I guess, it does not harm data segment to be 4K aligned.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If the microcode driver is built in (rather than module) there are some,
ehm, interesting effects happening due to the new "call out to userspace"
behavior that is introduced.. and which runs too early. The result is a
boot hang; which is really nasty.
The patch below is a minimally safe patch to fix this regression for 2.6.19
by just not requesting actual microcode updates during early boot. (That
is a good idea in general anyway)
The "real" fix is a lot more complex given the entire cpu hotplug scenario
(during cpu hotplug you normally need to load the microcode as well); but
the interactions for that are just really messy at this point; this fix at
least makes it work and avoids a full detangle of hotplug.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This reverts commit de09bddb9d. It tried
to reserve the MMCONFIG mmio memory ranges, but since the MMCONFIG
information is broken and often bogus (which is why we don't dare use it
most of the time _anyway_), it does more harm than good.
Cc: Jeff Chua <jeff.chua.linux@gmail.com>
Cc: Adrian Bunk <bunk@stusta.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Since the "mask" bit is in the low word, when we write a new entry, we
need to write the high word first, before we potentially unmask it.
The exception is when we actually want to mask the interrupt, in which
case we want to write the low word first to make sure that the high word
doesn't change while the interrupt routing is still active.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is preparation for fixing the ordering of the accesses that
got broken by the commit cf4c6a2f27 when
factoring out the "common" io apic routing entry accesses.
Move the accessor function (that were only used by io_apic.c) out
of a header file, and use proper memory-mapped accesses rather than
making up our own "volatile" pointers.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
APM BIOS Interface Secification can now be found at
http://www.microsoft.com/whdc/archive/amp_12.mspx
Signed-off-by: Kristian Mueller <Kristian-M@Kristian-M.de>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
efi_memory_present_wrapper() parameter start/end is physical address, but
function memory_present parameter is PFN, this patch converts physical
address to PFN.
Signed-off-by: bibo, mao <bibo.mao@intel.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6:
PCI: Remove quirk_via_abnormal_poweroff
PCI: reset pci device state to unknown state for resume
PCI: x86-64: mmconfig missing printk levels
PCI: fix pci_fixup_video as it blows up on sparc64
acpiphp: fix latch status
Add a vmlinux.lds.h helper macro for defining the eight-level initcall table,
teach all the architectures to use it.
This is a prerequisite for a patch which performs initcall synchronisation for
multithreaded-probing.
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
[ Added AVR32 as well ]
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This reverts much of the original pci_fixup_video change and makes it
work for all arches that need it.
fixed, and tested on x86, x86_64 and IA64 dig.
Signed-off-by: Eiichiro Oiwa <eiichiro.oiwa.nm@hitachi.com>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Jan convinced me that it was unnecessary because the assembly stubs do
this already on the stack.
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>
The fake return address was being set to __KERNEL_PDA, rather than 0.
Push it earlier while %eax still equals 0.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Andrew Morton <akpm@osdl.org>
This avoids some problems with gcc 4.x and earlier generating
invalid unwind information. In 4.1 the option is default
when unwind information is enabled.
And it seems to generate smaller code too, so it's probably
a good thing on its own. With gcc 4.0:
i386:
4683198 902112 480868 6066178 5c9002 vmlinux (before)
4449895 902112 480868 5832875 5900ab vmlinux (after)
x86-64:
4939761 1449584 648216 7037561 6b6279 vmlinux (before)
4854193 1449584 648216 6951993 6a1439 vmlinux (after)
On 4.1 it shouldn't make much difference because it is
default when unwind is enabled anyways.
Suggested by Michael Matz and Jan Beulich
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>
This was copied, pasted but not edited.
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Interrupts must be disabled during alternative instruction patching. On
systems with high timer IRQ rates, or when running in an emulator, timing
differences can result in random kernel panics because of running partially
patched instructions. This doesn't yet fix NMIs, which requires extricating
the patch code from the late bug checking and is logically separate (and also
less likely to cause problems).
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Separate out the concept of "queue congestion" from "backing-dev congestion".
Congestion is a backing-dev concept, not a queue concept.
The blk_* congestion functions are retained, as wrappers around the core
backing-dev congestion functions.
This proper layering is needed so that NFS can cleanly use the congestion
functions, and so that CONFIG_BLOCK=n actually links.
Cc: "Thomas Maier" <balagi@justmail.de>
Cc: "Jens Axboe" <jens.axboe@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: David Howells <dhowells@redhat.com>
Cc: Peter Osterlund <petero2@telia.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Problem:
New Dell PowerEdge servers have 2 embedded ethernet ports, which are
labeled NIC1 and NIC2 on the chassis, in the BIOS setup screens, and
in the printed documentation. Assuming no other add-in ethernet ports
in the system, Linux 2.4 kernels name these eth0 and eth1
respectively. Many people have come to expect this naming. Linux 2.6
kernels name these eth1 and eth0 respectively (backwards from
expectations). I also have reports that various Sun and HP servers
have similar behavior.
Root cause:
Linux 2.4 kernels walk the pci_devices list, which happens to be
sorted in breadth-first order (or pcbios_find_device order on i386,
which most often is breadth-first also). 2.6 kernels have both the
pci_devices list and the pci_bus_type.klist_devices list, the latter
is what is walked at driver load time to match the pci_id tables; this
klist happens to be in depth-first order.
On systems where, for physical routing reasons, NIC1 appears on a
lower bus number than NIC2, but NIC2's bridge is discovered first in
the depth-first ordering, NIC2 will be discovered before NIC1. If the
list were sorted breadth-first, NIC1 would be discovered before NIC2.
A PowerEdge 1955 system has the following topology which easily
exhibits the difference between depth-first and breadth-first device
lists.
-[0000:00]-+-00.0 Intel Corporation 5000P Chipset Memory Controller Hub
+-02.0-[0000:03-08]--+-00.0-[0000:04-07]--+-00.0-[0000:05-06]----00.0-[0000:06]----00.0 Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (labeled NIC2, 2.4 kernel name eth1, 2.6 kernel name eth0)
+-1c.0-[0000:01-02]----00.0-[0000:02]----00.0 Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (labeled NIC1, 2.4 kernel name eth0, 2.6 kernel name eth1)
Other factors, such as device driver load order and the presence of
PCI slots at various points in the bus hierarchy further complicate
this problem; I'm not trying to solve those here, just restore the
device order, and thus basic behavior, that 2.4 kernels had.
Solution:
The solution can come in multiple steps.
Suggested fix#1: kernel
Patch below optionally sorts the two device lists into breadth-first
ordering to maintain compatibility with 2.4 kernels. It adds two new
command line options:
pci=bfsort
pci=nobfsort
to force the sort order, or not, as you wish. It also adds DMI checks
for the specific Dell systems which exhibit "backwards" ordering, to
make them "right".
Suggested fix#2: udev rules from userland
Many people also have the expectation that embedded NICs are always
discovered before add-in NICs (which this patch does not try to do).
Using the PCI IRQ Routing Table provided by system BIOS, it's easy to
determine which PCI devices are embedded, or if add-in, which PCI slot
they're in. I'm working on a tool that would allow udev to name
ethernet devices in ascending embedded, slot 1 .. slot N order,
subsort by PCI bus/dev/fn breadth-first. It'll be possible to use it
independent of udev as well for those distributions that don't use
udev in their installers.
Suggested fix#3: system board routing rules
One can constrain the system board layout to put NIC1 ahead of NIC2
regardless of breadth-first or depth-first discovery order. This adds
a significant level of complexity to board routing, and may not be
possible in all instances (witness the above systems from several
major manufacturers). I don't want to encourage this particular train
of thought too far, at the expense of not doing #1 or #2 above.
Feedback appreciated. Patch tested on a Dell PowerEdge 1955 blade
with 2.6.18.
You'll also note I took some liberty and temporarily break the klist
abstraction to simplify and speed up the sort algorithm. I think
that's both safe and appropriate in this instance.
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
pci_fixup_video turns into generic code because there are many platforms need this fixup
for embedded VGA as well as x86. The Video BIOS integrates into System BIOS on a machine
has embedded VGA although embedded VGA generally don't have PCI ROM. As a result,
embedded VGA need the way that the sysfs rom points to the Video BIOS of System
RAM (0xC0000). PCI-to-PCI Bridge Architecture specification describes the condition whether
or not PCI ROM forwards VGA compatible memory address. fixup_video suits this specification.
Although the Video ROM generally implements in x86 code regardless of platform, some
application such as X Window System can run this code by dosemu86. Therefore,
pci_fixup_video should turn into generic code.
Signed-off-by: Eiichiro Oiwa <eiichiro.oiwa.nm@hitachi.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Introduce desc->name and eliminate the handle_irq_name() hack. Add
set_irq_chip_and_handler_name() to set the flow type and name at once.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Avoid possible PIT livelock issues seen on SMP systems (and reported by
Andi), by not allowing it as a clocksource on SMP boxes.
However, since the PIT may no longer be present, we have to properly handle
the cases where SMP systems have TSC skew and fall back from the TSC.
Since the PIT isn't there, it would "fall back" to the TSC again. So this
changes the jiffies rating to 1, and the TSC-bad rating value to 0.
Thus you will get the following behavior priority on i386 systems:
tsc [if present & stable]
hpet [if present]
cyclone [if present]
acpi_pm [if present]
pit [if UP]
jiffies
Rather then the current more complicated:
tsc [if present & stable]
hpet [if present]
cyclone [if present]
acpi_pm [if present]
pit [if cpus < 4]
tsc [if present & unstable]
jiffies
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The Linux group at Stratus Technologies has come across an issue with SCI
routing under ACPI. We were bitten by this when we made an x86_64 platform
whose BIOS provides an Interrupt Source Override for the SCI itself.
Apparently the override has no effect for the System Control Interrupt, and
this appears to be because of the way the SCI is setup in the ACPI code.
It does not handle the case where busirq != gsi.
The code that sets up the SCI routing assumes that bus irq == global irq.
So there is simply no provision for telling it otherwise. The attached
patch provides this mechanism.
This patch provided by David Bulkow, was tested on an i386 platform, which
does not use the SCI override, and also on an x86_64 platform which does
use an override.
Signed-off-by: David Bulkow <david.bulkow@stratus.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
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>
