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Introduce a core framework for run-time power management of I/O
devices. Add device run-time PM fields to 'struct dev_pm_info'
and device run-time PM callbacks to 'struct dev_pm_ops'. Introduce
a run-time PM workqueue and define some device run-time PM helper
functions at the core level. Document all these things.
Special thanks to Alan Stern for his help with the design and
multiple detailed reviews of the pereceding versions of this patch
and to Magnus Damm for testing feedback.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@igel.co.jp>
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Fix some issues with the AFS documentation, found when testing AFS on ppc64:
- Update AFS features: reading/writing, local caching
- Typo in kafs sysfs debug file
- Use modprobe instead of insmod in example
- Update IPs for grand.central.org
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to
the mm_struct. It was a very good first step for sanitize OOM.
However Paul Menage reported the commit makes regression to his job
scheduler. Current OOM logic can kill OOM_DISABLED process.
Why? His program has the code of similar to the following.
...
set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */
...
if (vfork() == 0) {
set_oom_adj(0); /* Invoked child can be killed */
execve("foo-bar-cmd");
}
....
vfork() parent and child are shared the same mm_struct. then above
set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also
change oom_adj for vfork() parent. Then, vfork() parent (job scheduler)
lost OOM immune and it was killed.
Actually, fork-setting-exec idiom is very frequently used in userland program.
We must not break this assumption.
Then, this patch revert commit 2ff05b2b and related commit.
Reverted commit list
---------------------
- commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct)
- commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE)
- commit 8123681022 (oom: only oom kill exiting tasks with attached memory)
- commit 933b787b57 (mm: copy over oom_adj value at fork time)
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Thanks to hermann pitton <hermann-pitton@arcor.de> for pointing this new
variation.
Tested-by: hermann pitton <hermann-pitton@arcor.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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WinTV-HVR1120 DVB-T/Hybrid
Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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WinTV-HVR1150 ATSC/QAM-Hybrid
Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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By default the kernel honors the HPA (host protected area) of hard
drives. Using libata's ignore_hpa module option it's possible to
change this behaviour.
Document usage and options of libata.ignore_hpa in
Documentation/kernel-parameters.txt.
Signed-off-by: Michael Prokop <mika@grml.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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This will register the ioctl range used by nilfs2 file system to the
table listed in Documentation/ioctl/ioctl-number.txt.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
lockdep: Fix typos in documentation
lockdep: Fix file mode of lock_stat
rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()
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* master.kernel.org:/home/rmk/linux-2.6-arm: (30 commits)
ARM: 5639/1: arm: clkdev.c should include <linux/clk.h>
ARM: 5638/1: arch/arm/kernel/signal.c: use correct address space for CRUNCH
ARM: 5637/1: [KS8695] Don't reference CLOCK_TICK_RATE in drivers
ARM: S3C64XX: serial: Fix section mismatch warning
ARM: S3C24XX: serial: Fix section mismatch warnings
ARM: S3C: PWM fix for low duty cycle
ARM: 5597/1: [PCI] reset all internal hardware prior PCI initialization
ARM: 5627/1: Fix restoring of lr at the end of mcount
ARM: 5624/1: Document cache aliasing region
S3C64XX: Fix ARMCLK configuration
S3C64XX: Fix get_rate() for ARMCLK
S3C24XX: GPIO: Fix pin range check in s3c_gpiolib_getchip
mx3 defconfig update
mx27 defconfig update
ARM: 5623/1: Treo680: ir shutdown typo fix
ARM: includecheck fix: plat-stmp3xxx/pinmux.c
ARM: includecheck fix: plat-s3c64xx/pm.c
ARM: includecheck fix: mach-omap2/mcbsp.c
ARM: includecheck fix: mach-omap1/mcbsp.c
ARM: includecheck fix: board-sffsdr.c
...
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s/head/held
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4A7BD37E.9060806@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
Make SCSI SG v4 driver enabled by default and remove EXPERIMENTAL dependency, since udev depends on BSG
block: Update topology documentation
block: Stack optimal I/O size
block: Add a wrapper for setting minimum request size without a queue
block: Make blk_queue_stack_limits use the new stacking interface
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (47 commits)
ehea: Fix napi list corruption on ifconfig down
igbvf: Allow VF driver to correctly recognize failure to set mac
3c59x: Fix build failure with gcc 3.2
sky2: Avoid transmits during sky2_down()
iwlagn: do not send key clear commands when rfkill enabled
libertas: Read buffer overflow
drivers/net/wireless: introduce missing kfree
drivers/net/wireless/iwlwifi: introduce missing kfree
zd1211rw: fix unaligned access in zd_mac_rx
cfg80211: fix regression on beacon world roaming feature
cfg80211: add two missing NULL pointer checks
ixgbe: Patch to modify 82598 PCIe completion timeout values
bluetooth: rfcomm_init bug fix
mlx4_en: Fix double pci unmapping.
mISDN: Fix handling of receive buffer size in L1oIP
pcnet32: VLB support fixes
pcnet32: remove superfluous NULL pointer check in pcnet32_probe1()
net: restore the original spinlock to protect unicast list
netxen: fix coherent dma mask setting
mISDN: Read buffer overflow
...
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The standard ACPI dock driver can handle the hotplug bays and docks of
the ThinkPads just fine (including batteries) as of 2.6.27, and the
code in thinkpad-acpi for the dock and bay subdrivers is currently
broken anyway...
Userspace needs some love to support the two-stage ejection nicely,
but it is simple enough to do through udev rules (you don't even need
HAL) so this wouldn't justify fixing the dock and bay subdrivers,
either.
That leaves warm-swap bays (_EJ3) support for thinkpad-acpi, as well
as support for the weird dock of the model 570, but since such support
has never left the "experimental" stage, it is also not a strong
enough reason to find a way to fix this code.
Users of ThinkPads with warm-swap bays are urged to request that _EJ3
support be added to the regular ACPI dock driver, if such feature is
indeed useful for them.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>
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Update topology comments and sysfs documentation based upon discussions
with Neil Brown.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Use the %pI4 format string instead of %d.%d.%d.%d and NIPQUAD.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Augment the memory.txt file for ARM to list the cache aliasing
region ffff4000-fffffff.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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I've been doing this for years, and akpm picked me up on it about 12
months ago. lguest partly serves as example code, so let's do it Right.
Also, remove two unused fields in struct vblk_info in the example launcher.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
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Every so often, after code shuffles, I need to go through and unbitrot
the Lguest Journey (see drivers/lguest/README). Since we now use RCU in
a simple form in one place I took the opportunity to expand that explanation.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
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I don't really notice it (except to begrudge the extra vertical
space), but Ingo does. And he pointed out that one excuse of lguest
is as a teaching tool, it should set a good example.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
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1d589bb16b825b3a7b4edd34d997f1f1f953033d "Add serial number support
for virtio_blk, V4a" extended 'struct virtio_blk_config' to 536 bytes.
Lguest and S/390 both use an 8 bit value for the feature length, and
this change broke them (if the code is naive).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: John Cooper <john.cooper@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
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commit d6580a9f15238b87e618310c862231ae3f352d2d ("kexec: sysrq: simplify
sysrq-c handler") changed the behavior of sysrq-c to unconditional
dereference of NULL pointer. So in cases with CONFIG_KEXEC, where
crash_kexec() was directly called from sysrq-c before, now it can be said
that a step of "real oops" was inserted before starting kdump.
However, in contrast to oops via SysRq-c from keyboard which results in
panic due to in_interrupt(), oops via "echo c > /proc/sysrq-trigger" will
not become panic unless panic_on_oops=1. It means that even if dump is
properly configured to be taken on panic, the sysrq-c from proc interface
might not start crashdump while the sysrq-c from keyboard can start
crashdump. This confuses traditional users of kdump, i.e. people who
expect sysrq-c to do common behavior in both of the keyboard and proc
interface.
This patch brings the keyboard and proc interface behavior of sysrq-c in
line, by forcing panic_on_oops=1 before oops in sysrq-c handler.
And some updates in documentation are included, to clarify that there is
no longer dependency with CONFIG_KEXEC, and that now the system can just
crash by sysrq-c if no dump mechanism is configured.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Brayan Arraes <brayan@yack.com.br>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The original text suggested that sysfs is mandatory and always
compiled in the kernel.
Signed-off-by: Lucian Adrian Grijincu <lgrijincu@ixiacom.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: hda - Fix mute control with some ALC262 models
ALSA: snd_usb_caiaq: add support for Audio2DJ
ALSA: pcm - Fix hwptr buffer-size overlap bug
ALSA: pcm - Fix warnings in debug loggings
ALSA: pcm - Add logging of hwptr updates and interrupt updates
ASoC: tlv320aic3x: Enable PLL when not bypassed
ALSA: hda - Restore GPIO1 properly at resume with AD1984A
ALSA: ctxfi - Fix uninitialized error checks
ALSA: hda - Use snprintf() to be safer
ALSA: usb-audio - Volume control quirk for QuickCam E 3500
ALSA: pcm - Fix regressions with VMware
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* fix/pcm-hwptr:
ALSA: pcm - Fix hwptr buffer-size overlap bug
ALSA: pcm - Fix warnings in debug loggings
ALSA: pcm - Add logging of hwptr updates and interrupt updates
ALSA: pcm - Fix regressions with VMware
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Signed-off-by: Brian Johnson <brijohn@gmail.com>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Webcams in general don't have eeprom. So, the sensor hint code should be
called to properly detect what sensor is inside.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Added the logging functionality to xrun_debug to record the hwptr
updates via snd_pcm_update_hw_ptr() and snd_pcm_update_hwptr_interrupt(),
corresponding to 16 and 8, respectively.
For example,
# echo 9 > /proc/asound/card0/pcm0p/xrun_debug
will record the position and other parameters at each period interrupt
together with the normal XRUN debugging.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (37 commits)
sky2: Avoid races in sky2_down
drivers/net/mlx4: Adjust constant
drivers/net: Move a dereference below a NULL test
drivers/net: Move a dereference below a NULL test
connector: maintainer/mail update.
USB host CDC Phonet network interface driver
macsonic, jazzsonic: fix oops on module unload
macsonic: move probe function to .devinit.text
can: switch carrier on if device was stopped while in bus-off state
can: restart device even if dev_alloc_skb() fails
can: sja1000: remove duplicated includes
New device ID for sc92031 [1088:2031]
3c589_cs: re-initialize the multicast in the tc589_reset
Fix error return for setsockopt(SO_TIMESTAMPING)
netxen: fix thermal check and shutdown
netxen: fix deadlock on dev close
netxen: fix context deletion sequence
net: Micrel KS8851 SPI network driver
tcp: Use correct peer adr when copying MD5 keys
tcp: Fix MD5 signature checking on IPv4 mapped sockets
...
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Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The kernel has used a stale email address of Andreas for a few years.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-2.6
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git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-sched
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-sched:
sched: Fix bug in SCHED_IDLE interaction with group scheduling
sched: Fix rt_rq->pushable_tasks initialization in init_rt_rq()
sched: Reset sched stats on fork()
sched_rt: Fix overload bug on rt group scheduling
sched: Documentation/sched-rt-group: Fix style issues & bump version
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When a slab cache uses SLAB_DESTROY_BY_RCU, we must be careful when allocating
objects, since slab allocator could give a freed object still used by lockless
readers.
In particular, nf_conntrack RCU lookups rely on ct->tuplehash[xxx].hnnode.next
being always valid (ie containing a valid 'nulls' value, or a valid pointer to next
object in hash chain.)
kmem_cache_zalloc() setups object with NULL values, but a NULL value is not valid
for ct->tuplehash[xxx].hnnode.next.
Fix is to call kmem_cache_alloc() and do the zeroing ourself.
As spotted by Patrick, we also need to make sure lookup keys are committed to
memory before setting refcount to 1, or a lockless reader could get a reference
on the old version of the object. Its key re-check could then pass the barrier.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
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FIX prototypes for show & store method in struct driver_attribute
Signed-off-by: vibi sreenivasan <vibi_sreenivasan@cms.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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exception.txt only explains the code on x86, so it's better to
move it into Documentation/x86 directory.
And also rename it to exception-tables.txt which looks much
more reasonable.
This patch is on top of the previous one.
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Update Documentation/exception.txt.
Remove trailing whitespaces in it.
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
dma-debug: Fix the overlap() function to be correct and readable
oprofile: reset bt_lost_no_mapping with other stats
x86/oprofile: rename kernel parameter for architectural perfmon to arch_perfmon
signals: declare sys_rt_tgsigqueueinfo in syscalls.h
rcu: Mark Hierarchical RCU no longer experimental
dma-debug: Put all hash-chain locks into the same lock class
dma-debug: fix off-by-one error in overlap function
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (29 commits)
cxgb3: Fix crash caused by stashing wrong netdev_queue
ixgbe: Fix coexistence of FCoE and Flow Director in 82599
memory barrier: adding smp_mb__after_lock
net: adding memory barrier to the poll and receive callbacks
netpoll: Fix carrier detection for drivers that are using phylib
includecheck fix: include/linux, rfkill.h
p54: tx refused but queue active
Atheros Kconfig needs to be dependent on WLAN_80211
mac80211: fix docbook
mac80211_hwsim: avoid NULL access
ssb: Add support for 4318E
b43: Add support for 4318E
zd1211rw: adding SONY IFU-WLM2 (054c:0257) as a zd1211b device
zd1211rw: 07b8:6001 is a ZD1211B
r6040: bump driver version to 0.24 and date to 08 July 2009
r6040: restore MIER register correctly when IRQ line is shared
ipv4: Fix fib_trie rebalancing, part 4 (root thresholds)
davinci_emac: fix kernel oops when changing MAC address while interface is down
igb: set lan id prior to configuring phy
mac80211: minstrel: avoid accessing negative indices in rix_to_ndx()
...
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The short name of the achitecture is 'arch_perfmon'. This patch
changes the kernel parameter to use this name.
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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These two functions no longer exist in mac80211,
so trying to insert them generates warnings in
the document.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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lock_policy_rwsem_* and unlock_policy_rwsem_* routines in cpufreq.c are
currently exported to drivers. Improper use of those locks can
result in deadlocks and it is better to keep the locks localized.
Two previous in-kernel users of these interfaces (ondemand and conservative),
do not use this interfaces any more. Schedule them for removal.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
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extraction logic
The extraction routine for the MPC718 "firmware" had 2 bugs in it, where one
bug masked the effect of the other. The loop iteration should have set
$prevlen = $currlen at the end of the loop, and the if() check should have used
&& instead of || for deciding if the firmware length is reasonable.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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This webcam uses a em2710 chipset, that identifies itself as em2820,
plus a mt9v011 sensor, and a DY-301P lens.
It needs a few different initializations than a normal em28xx device.
Thanks to Hans de Goede <hdegoede@redhat.com> and Douglas Landgraf
<dougsland@redhat.com> for providing the acces for the webcam during
this weekend, I could make a patch for it while returning back from
FISL/Fudcom LATAM 2009.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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extraction
Add routine to support extracting the MT352 DVB-T demodulator initialization
sequence for Yuan MPC718 cards for use by the cx18 driver.
This routine uses a hueristic for extracting a good sequence. It should work
on all different versions of the "yuanrap.sys" file, given the way the MT352
tuning sequences are stored in all versions of that file I have seen so far.
However, the current patch simply looks for one specific archive URL.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Signed-off-by: Andre Noll <maan@systemlinux.org>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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* 'kmemleak' of git://linux-arm.org/linux-2.6:
kmemleak: Inform kmemleak about pid_hash
kmemleak: Do not warn if an unknown object is freed
kmemleak: Do not report new leaked objects if the scanning was stopped
kmemleak: Slightly change the policy on newly allocated objects
kmemleak: Do not trigger a scan when reading the debug/kmemleak file
kmemleak: Simplify the reports logged by the scanning thread
kmemleak: Enable task stacks scanning by default
kmemleak: Allow the early log buffer to be configurable.
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By writing a tasks's pid to the file, a process adds that task to that
cgroup/cpuset. But to add a cpu/mem to a cpuset, the new list of cpus
should be written to the cpuset.mems file which would replace the old list
of cpus. Make this clearer in the documentation.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add two new spi_device.mode bits to accomodate more protocol options, and
pass them through to usermode drivers:
* SPI_NO_CS ... a second 3-wire variant, where the chipselect
line is removed instead of a data line; transfers are still
full duplex.
This obviously has STRONG protocol implications since the
chipselect transitions can't be used to synchronize state
transitions with the SPI master.
* SPI_READY ... defines open drain signal that's pulled low
to pause the clock. This defines a 5-wire variant (normal
4-wire SPI plus READY) and two 4-wire variants (READY plus
each of the 3-wire flavors).
Such hardware flow control can be a big win. There are ADC
converters and flash chips that expose READY signals, but not
many host controllers support it today.
The spi_bitbang code should be changed to use SPI_NO_CS instead of its
current nonportable hack. That's a mode most hardware can easily support
(unlike SPI_READY).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: "Paulraj, Sandeep" <s-paulraj@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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