The recent EC cleanup left a printk enabled on handler evaluation
resulting in a bunch of messages on normal operation, like so:
ACPI: EC: evaluating _Q60
Signed-off-by: Len Brown <len.brown@intel.com>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (68 commits)
ACPI: replace kmalloc+memset with kzalloc
ACPI: Add support for acpi_load_table/acpi_unload_table_id
fbdev: update after backlight argument change
ACPI: video: Add dev argument for backlight_device_register
ACPI: Implement acpi_video_get_next_level()
ACPI: Kconfig - depend on PM rather than selecting it
ACPI: fix NULL check in drivers/acpi/osl.c
ACPI: make drivers/acpi/ec.c:ec_ecdt static
ACPI: prevent processor module from loading on failures
ACPI: fix single linked list manipulation
ACPI: ibm_acpi: allow clean removal
ACPI: fix git automerge failure
ACPI: ibm_acpi: respond to workqueue update
ACPI: dock: add uevent to indicate change in device status
ACPI: ec: Lindent once again
ACPI: ec: Change #define to enums there possible.
ACPI: ec: Style changes.
ACPI: ec: Acquire Global Lock under EC mutex.
ACPI: ec: Drop udelay() from poll mode. Loop by reading status field instead.
ACPI: ec: Rename gpe_bit to gpe
...
Fernando Lopez-Lezcano reported frequent scheduling latencies and audio
xruns starting at the 2.6.18-rt kernel, and those problems persisted all
until current -rt kernels. The latencies were serious and unjustified by
system load, often in the milliseconds range.
After a patient and heroic multi-month effort of Fernando, where he
tested dozens of kernels, tried various configs, boot options,
test-patches of mine and provided latency traces of those incidents, the
following 'smoking gun' trace was captured by him:
_------=> CPU#
/ _-----=> irqs-off
| / _----=> need-resched
|| / _---=> hardirq/softirq
||| / _--=> preempt-depth
|||| /
||||| delay
cmd pid ||||| time | caller
\ / ||||| \ | /
IRQ_19-1479 1D..1 0us : __trace_start_sched_wakeup (try_to_wake_up)
IRQ_19-1479 1D..1 0us : __trace_start_sched_wakeup <<...>-5856> (37 0)
IRQ_19-1479 1D..1 0us : __trace_start_sched_wakeup (c01262ba 0 0)
IRQ_19-1479 1D..1 0us : resched_task (try_to_wake_up)
IRQ_19-1479 1D..1 0us : __spin_unlock_irqrestore (try_to_wake_up)
...
<idle>-0 1...1 11us!: default_idle (cpu_idle)
...
<idle>-0 0Dn.1 602us : smp_apic_timer_interrupt (c0103baf 1 0)
...
<...>-5856 0D..2 618us : __switch_to (__schedule)
<...>-5856 0D..2 618us : __schedule <<idle>-0> (20 162)
<...>-5856 0D..2 619us : __spin_unlock_irq (__schedule)
<...>-5856 0...1 619us : trace_stop_sched_switched (__schedule)
<...>-5856 0D..1 619us : trace_stop_sched_switched <<...>-5856> (37 0)
what is visible in this trace is that CPU#1 ran try_to_wake_up() for
PID:5856, it placed PID:5856 on CPU#0's runqueue and ran resched_task()
for CPU#0. But it decided to not send an IPI that no CPU - due to
TS_POLLING. But CPU#0 never woke up after its NEED_RESCHED bit was set,
and only rescheduled to PID:5856 upon the next lapic timer IRQ. The
result was a 600+ usecs latency and a missed wakeup!
the bug turned out to be an idle-wakeup bug introduced into the mainline
kernel this summer via an optimization in the x86_64 tree:
commit 495ab9c045
Author: Andi Kleen <ak@suse.de>
Date: Mon Jun 26 13:59:11 2006 +0200
[PATCH] i386/x86-64/ia64: Move polling flag into thread_info_status
During some profiling I noticed that default_idle causes a lot of
memory traffic. I think that is caused by the atomic operations
to clear/set the polling flag in thread_info. There is actually
no reason to make this atomic - only the idle thread does it
to itself, other CPUs only read it. So I moved it into ti->status.
the problem is this type of change:
if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
- clear_thread_flag(TIF_POLLING_NRFLAG);
+ current_thread_info()->status &= ~TS_POLLING;
smp_mb__after_clear_bit();
while (!need_resched()) {
local_irq_disable();
this changes clear_thread_flag() to an explicit clearing of TS_POLLING.
clear_thread_flag() is defined as:
clear_bit(flag, &ti->flags);
and clear_bit() is a LOCK-ed atomic instruction on all x86 platforms:
static inline void clear_bit(int nr, volatile unsigned long * addr)
{
__asm__ __volatile__( LOCK_PREFIX
"btrl %1,%0"
hence smp_mb__after_clear_bit() is defined as a simple compile barrier:
#define smp_mb__after_clear_bit() barrier()
but the explicit TS_POLLING clearing introduced by the patch:
+ current_thread_info()->status &= ~TS_POLLING;
is not an atomic op! So the clearing of the TS_POLLING bit is freely
reorderable with the reading of the NEED_RESCHED bit - and both now
reside in different memory addresses.
CPU idle wakeup very much depends on ordered memory ops, the clearing of
the TS_POLLING flag must always be done before we test need_resched()
and hit the idle instruction(s). [Symmetrically, the wakeup code needs
to set NEED_RESCHED before it tests the TS_POLLING flag, so memory
ordering is paramount.]
Fernando's dual-core Athlon64 system has a sufficiently advanced memory
ordering model so that it triggered this scenario very often.
( And it also turned out that the reason why these latencies never
triggered on my testsystems is that i routinely use idle=poll, which
was the only idle variant not affected by this bug. )
The fix is to change the smp_mb__after_clear_bit() to an smp_mb(), to
act as an absolute barrier between the TS_POLLING write and the
NEED_RESCHED read. This affects almost all idling methods (default,
ACPI, APM), on all 3 x86 architectures: i386, x86_64, ia64.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a prototype for driver_init() in include/linux/device.h.
Also remove a static function of the same name in drivers/acpi/ibm_acpi.c to
ibm_acpi_driver_init() to fix the namespace collision.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make acpi_load_table() available for use by removing it from the #ifdef
ACPI_FUTURE_USAGE.
Also add a new routine used to unload an ACPI table of a given type and "id" -
acpi_unload_table_id(). The implementation of this new routine was almost a
direct copy of existing routine acpi_unload_table() - only difference being
that it only removes a specific table id instead of ALL tables of a given
type. The SN hotplug driver (sgi_hotplug.c) now uses both of these interfaces
to dynamically load and unload SSDT ACPI tables.
Also, a few other ACPI routines now used by the SN hotplug driver are exported
(since the driver can be a loadable module):
acpi_ns_map_handle_to_node
acpi_ns_convert_entry_to_handle
acpi_ns_get_next_node
Signed-off-by: Aaron Young <ayoung@sgi.com>
Cc: Greg KH <greg@kroah.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
This patch set adds generic abstract layer support for acpi video driver to
have generic user interface to control backlight and output switch control by
leveraging the existing backlight sysfs class driver, and by adding a new
video output sysfs class driver.
This patch:
Add dev argument for backlight_device_register to link the class device to
real device object. The platform specific driver should find a way to get the
real device object for their video device.
[akpm@osdl.org: build fix]
[akpm@osdl.org: fix msi-laptop.c]
Signed-off-by: Luming Yu <Luming.yu@intel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
acpi_video_get_next_level was supposed to implement an algorithm to select
a new brightness level based on the old brightness level of an ACPI video
device, but it simply says "/* Fix me */" and returns the current
brightness.
This patch implements acpi_video_get_next_level properly. It had to change
a few constants at the top of the file because they were (apparently)
wrong, but it appears to work on my Dell Inspiron e1405 (with BIOS A05
only--BIOS A04 doesn't seem to send ACPI video hotkey events).
[akpm@osdl.org: cleanups]
Signed-off-by: Thomas Tuttle <linux-kernel@ttuttle.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Make ACPI depend on PM rather than selecting it.
Otherwise it's a nightmare working out why CONFIG_PM keeps getting set.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Spotted by the Coverity checker.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Make loading processor.ko fail when an error happens.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Fix single linked list manipulation for sub_driver. If the remving entry
is not on the head of the sub_driver list, it goes into infinate loop.
Though that infinite loop doesn't happen. Because the only user of
acpi_pci_register_dirver() is acpiphp.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
Allow clean removal by setting notify_installed in the right place.
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>
Send a uevent to indicate a device change whenever we dock or
undock, so that userspace may now check the dock status via sysfs.
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Fix bug which will cause acpiphp to not be able to load when dock.ko
cannot load.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Add 2 sysfs files for user interface.
1) docked - 1/0 (read only) - indicates whether the software believes the
laptop is docked in a docking station.
2) undock - (write only) - writing to this file causes the software to
initiate an undock request to the firmware.
Signed-off-by: Brandon Philips <brandon@ifup.org>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Make the dock station driver a platform device driver so that
we can create sysfs entries under /sys/device/platform.
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This patch cleans up the recently added backlight device support by Holger
Macht <hmacht@suse.de> to fit well with the rest of the code, using the
ibms struct as the other "subdrivers" in ibm-acpi.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
This patch makes it possible to disable ibm-acpi non-generic bay support,
as generic bay support already works well for a number of ThinkPads.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
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>
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>
Guillaume Chazarain