openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity
linux/Documentation
History
Rafael J. Wysocki 1e2ef05bb8 PM: Limit race conditions between runtime PM and system sleep (v2) 
One of the roles of the PM core is to prevent different PM callbacks
executed for the same device object from racing with each other.
Unfortunately, after commit e866500247
(PM: Allow pm_runtime_suspend() to succeed during system suspend)
runtime PM callbacks may be executed concurrently with system
suspend/resume callbacks for the same device.

The main reason for commit e866500247
was that some subsystems and device drivers wanted to use runtime PM
helpers, pm_runtime_suspend() and pm_runtime_put_sync() in
particular, for carrying out the suspend of devices in their
.suspend() callbacks.  However, as it's been determined recently,
there are multiple reasons not to do so, inlcuding:

 * The caller really doesn't control the runtime PM usage counters,
   because user space can access them through sysfs and effectively
   block runtime PM.  That means using pm_runtime_suspend() or
   pm_runtime_get_sync() to suspend devices during system suspend
   may or may not work.

 * If a driver calls pm_runtime_suspend() from its .suspend()
   callback, it causes the subsystem's .runtime_suspend() callback to
   be executed, which leads to the call sequence:

   subsys->suspend(dev)
      driver->suspend(dev)
         pm_runtime_suspend(dev)
            subsys->runtime_suspend(dev)

   recursive from the subsystem's point of view.  For some subsystems
   that may actually work (e.g. the platform bus type), but for some
   it will fail in a rather spectacular fashion (e.g. PCI).  In each
   case it means a layering violation.

 * Both the subsystem and the driver can provide .suspend_noirq()
   callbacks for system suspend that can do whatever the
   .runtime_suspend() callbacks do just fine, so it really isn't
   necessary to call pm_runtime_suspend() during system suspend.

 * The runtime PM's handling of wakeup devices is usually different
   from the system suspend's one, so .runtime_suspend() may simply be
   inappropriate for system suspend.

 * System suspend is supposed to work even if CONFIG_PM_RUNTIME is
   unset.

 * The runtime PM workqueue is frozen before system suspend, so if
   whatever the driver is going to do during system suspend depends
   on it, that simply won't work.

Still, there is a good reason to allow pm_runtime_resume() to
succeed during system suspend and resume (for instance, some
subsystems and device drivers may legitimately use it to ensure that
their devices are in full-power states before suspending them).
Moreover, there is no reason to prevent runtime PM callbacks from
being executed in parallel with the system suspend/resume .prepare()
and .complete() callbacks and the code removed by commit
e866500247 went too far in this
respect.  On the other hand, runtime PM callbacks, including
.runtime_resume(), must not be executed during system suspend's
"late" stage of suspending devices and during system resume's "early"
device resume stage.

Taking all of the above into consideration, make the PM core
acquire a runtime PM reference to every device and resume it if
there's a runtime PM resume request pending right before executing
the subsystem-level .suspend() callback for it.  Make the PM core
drop references to all devices right after executing the
subsystem-level .resume() callbacks for them.  Additionally,
make the PM core disable the runtime PM framework for all devices
during system suspend, after executing the subsystem-level .suspend()
callbacks for them, and enable the runtime PM framework for all
devices during system resume, right before executing the
subsystem-level .resume() callbacks for them.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
 		2011-07-06 10:51:58 +02:00
..
ABI backlight: new driver for the ADP8870 backlight devices 2011-06-15 20:03:59 -07:00
DocBook Merge git://git.infradead.org/mtd-2.6 2011-05-27 20:06:53 -07:00
PCI Fix common misspellings 2011-03-31 11:26:23 -03:00
RCU rcu: Decrease memory-barrier usage based on semi-formal proof 2011-05-26 09:42:23 -07:00
accounting Documentation: update cgroupfs mount point 2011-06-15 21:52:50 -07:00
acpi ACPI: Split out custom_method functionality into an own driver 2011-05-29 01:50:40 -04:00
aoe Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
arm Merge branch 'for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung into devel-stable 2011-05-25 21:47:48 +01:00
auxdisplay includecheck fix: Documentation, cfag12864b-example.c 2009-09-24 07:20:57 -07:00
blackfin Blackfin: document SPI CS limitations with CPHA=0 2010-08-06 12:55:52 -04:00
block Fix common misspellings 2011-03-31 11:26:23 -03:00
blockdev cciss: add cciss_tape_cmds module paramter 2011-05-06 08:23:59 -06:00
cdrom Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
cgroups Documentation: fix cgroup typos and formatting 2011-06-15 21:52:50 -07:00
connector Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
console doc: fix console doc typo 2010-02-24 13:51:32 +01:00
cpu-freq [CPUFREQ] Add documentation for sampling_down_factor 2011-03-16 17:54:31 -04:00
cpuidle
…
cris
…
crypto async_tx: add support for asynchronous RAID6 recovery operations 2009-08-29 19:09:27 -07:00
development-process docs: update the development process document 2011-03-25 14:30:31 -06:00
device-mapper Fix common misspellings 2011-03-31 11:26:23 -03:00
devicetree Merge branches 'devel', 'devel-stable' and 'fixes' into for-linus 2011-05-27 22:59:57 +01:00
driver-model driver core: remove the driver-model structures from the documentation 2011-05-06 18:01:05 -07:00
dvb Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
early-userspace
…
fault-injection lkdtm: add debugfs access and loosen KPROBE ties 2010-03-06 11:26:32 -08:00
fb Fix common misspellings 2011-03-31 11:26:23 -03:00
filesystems rcu: Use softirq to address performance regression 2011-06-14 15:25:39 -07:00
firmware_class firmware: Update hotplug script 2010-08-05 13:53:34 -07:00
frv
…
hid HID: Move hiddev.txt to the new Documentation/hid directory 2011-03-22 11:43:51 +01:00
hwmon hwmon: New driver for the SMSC EMC6W201 2011-05-25 20:43:33 +02:00
i2c i2c-i801: SMBus patch for Intel Panther Point DeviceIDs 2011-05-24 20:58:49 +02:00
i2o Fix common misspellings 2011-03-31 11:26:23 -03:00
ia64 Fix common misspellings 2011-03-31 11:26:23 -03:00
ide ide: preserve Host Protected Area by default (v2) 2009-06-07 13:52:52 +02:00
infiniband Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
input Input: elantech - describe further the protocol 2011-05-16 22:48:24 -07:00
ioctl Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc 2011-05-25 16:55:55 -07:00
isdn Fix common misspellings 2011-03-31 11:26:23 -03:00
ja_JP HOWTO: sync up Documentaion/ja_JP/HOWTO 2011-04-19 16:53:45 -07:00
kbuild Merge branch 'kconfig-for-40' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2011-05-25 16:54:01 -07:00
kdump kdump: update kexec-tools URL and Vivek's email 2010-11-25 14:36:38 +01:00
ko_KR Docs/Kconfig: Update: osdl.org -> linuxfoundation.org 2010-11-15 23:50:13 +01:00
laptops acer-wmi: Delete out-of-date documentation 2011-05-27 12:36:46 -04:00
leds Documentation: consolidate leds files to leds/ subdir 2011-04-04 17:51:47 -07:00
m68k
…
make kbuild: introduce HDR_ARCH_LIST for headers_install_all 2010-12-14 22:16:19 +01:00
mips Fix common misspellings 2011-03-31 11:26:23 -03:00
misc-devices Fix common misspellings 2011-03-31 11:26:23 -03:00
mmc mmc: MMC boot partitions support. 2011-05-24 21:01:21 -04:00
mn10300 trivial: Miscellaneous documentation typo fixes 2009-06-12 18:01:47 +02:00
mtd Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
namespaces
…
netlabel Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
networking Merge branch 'docs-move' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs 2011-05-27 10:25:02 -07:00
nfc NFC: Driver for NXP Semiconductors PN544 NFC chip. 2011-01-13 08:03:19 -08:00
parisc
…
pcmcia pcmcia: use autoconfiguration feature for ioports and iomem 2010-09-29 17:20:24 +02:00
power PM: Limit race conditions between runtime PM and system sleep (v2) 2011-07-06 10:51:58 +02:00
powerpc Fix common misspellings 2011-03-31 11:26:23 -03:00
pps pps: add parallel port PPS signal generator 2011-01-13 08:03:21 -08:00
prctl
…
pti Kernel documentation for the PTI feature. 2011-05-13 16:31:00 -07:00
ptp ptp: Added a brand new class driver for ptp clocks. 2011-05-23 13:01:00 -07:00
rapidio rapidio: add RapidIO documentation 2011-03-23 19:46:41 -07:00
s390 Documentation: fix minor typos/spelling 2011-04-04 17:51:47 -07:00
scheduler Documentation: update cgroupfs mount point 2011-06-15 21:52:50 -07:00
scsi [SCSI] megaraid_sas: Version and Changelog update 2011-05-24 12:36:06 -04:00
security Create Documentation/security/, 2011-05-19 15:59:38 -07:00
serial Fix common misspellings 2011-03-31 11:26:23 -03:00
sh sh: clkfwk: Kill off unused clk_set_rate_ex(). 2010-11-15 18:25:12 +09:00
sound Merge branch 'topic/hda' into for-linus 2011-05-22 10:01:35 +02:00
sparc
…
spi Fix common misspellings 2011-03-31 11:26:23 -03:00
sysctl coredump: add support for exe_file in core name 2011-05-26 17:12:36 -07:00
target [SCSI] tcm_mod_builder.py: Fix generated *_drop_nodeacl() handler 2011-03-23 11:36:45 -05:00
telephony Fix common misspellings 2011-03-31 11:26:23 -03:00
thermal thermal: Add event notification to thermal framework 2011-01-12 00:08:35 -05:00
timers doc: timers-howto: fix a typo ("unsgined") 2011-05-17 10:52:02 +02:00
trace sched: Get rid of lock_depth 2011-04-24 13:18:38 +02:00
usb USB: Fix up URB error codes to reflect implementation. 2011-06-17 11:28:21 -07:00
video4linux [media] uvcvideo: Add driver documentation 2011-05-20 09:30:36 -03:00
virtual lguest: remove support for VIRTIO_F_NOTIFY_ON_EMPTY. 2011-05-30 11:14:12 +09:30
vm Documentation: update cgroupfs mount point 2011-06-15 21:52:50 -07:00
w1 Fix common misspellings 2011-03-31 11:26:23 -03:00
watchdog Fix common misspellings 2011-03-31 11:26:23 -03:00
wimax i2400m: documentation and instructions for usage 2009-01-07 10:00:18 -08:00
x86 x86, gart: Rename pci-gart_64.c to amd_gart_64.c 2011-05-10 17:22:06 +02:00
zh_CN Translated Documentation/email-clients.txt 2011-05-06 17:59:20 -07:00
.gitignore add random binaries to .gitignore 2010-04-08 11:34:34 +02:00
00-INDEX Merge branch 'docs-security' into docs-move 2011-05-20 09:10:04 -07:00
BUG-HUNTING
…
Changes Documentation/Changes: minor corrections 2011-03-22 17:44:17 -07:00
CodingStyle Documentation/CodingStyle: flesh out if-else examples 2011-03-22 17:44:16 -07:00
DMA-API-HOWTO.txt Documentation: DMA-API-HOWTO.txt: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN 2010-08-14 11:56:46 -07:00
DMA-API.txt dma-mapping: remove dma_is_consistent API 2010-08-11 08:59:21 -07:00
DMA-ISA-LPC.txt
…
DMA-attributes.txt
…
HOWTO Documentation: update LXR web link 2011-05-23 15:14:11 -07:00
IPMI.txt IPMI: Add the document description of ipmi_get_smi_info 2010-12-14 00:22:00 -05:00
IRQ-affinity.txt bitmap, irq: add smp_affinity_list interface to /proc/irq 2011-05-25 08:39:45 -07:00
IRQ.txt
…
Intel-IOMMU.txt intel-iommu: Kill DMAR_BROKEN_GFX_WA option. 2009-09-19 09:37:23 -07:00
Makefile [media] Remove the old V4L1 v4lgrab.c file 2010-12-29 08:17:12 -02:00
ManagementStyle
…
SAK.txt
…
SM501.txt trivial: Miscellaneous documentation typo fixes 2009-06-12 18:01:47 +02:00
SecurityBugs Fix common misspellings 2011-03-31 11:26:23 -03:00
SubmitChecklist Documentation: update SubmitChecklist for O=objdir and kconfig testing 2010-05-24 07:31:20 -07:00
SubmittingDrivers Fix common misspellings 2011-03-31 11:26:23 -03:00
SubmittingPatches Documentation: update GregKH links 2011-05-23 15:14:11 -07:00
VGA-softcursor.txt
…
applying-patches.txt
…
atomic_ops.txt Documentation/atomic_ops.txt: avoid volatile in sample code 2011-05-26 17:12:34 -07:00
bad_memory.txt
…
basic_profiling.txt
…
binfmt_misc.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
braille-console.txt trivial: Miscellaneous documentation typo fixes 2009-06-12 18:01:47 +02:00
bt8xxgpio.txt
…
btmrvl.txt Bluetooth: Add documentation for Marvell Bluetooth driver 2009-08-22 14:25:32 -07:00
bus-virt-phys-mapping.txt documentation: fix almost duplicate filenames (IO/io-mapping.txt) 2010-07-20 17:49:30 +00:00
cachetlb.txt mm: convert mm->cpu_vm_cpumask into cpumask_var_t 2011-05-25 08:39:21 -07:00
circular-buffers.txt Document Linux's circular buffering capabilities 2010-03-24 16:31:22 -07:00
coccinelle.txt scripts/coccinelle: update for compatability with Coccinelle 0.2.4 2010-12-03 12:27:01 +01:00
cpu-hotplug.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
cpu-load.txt
…
cputopology.txt topology/sysfs: Provide book id and siblings attributes 2010-09-09 20:41:25 +02:00
dcdbas.txt
…
debugging-modules.txt
…
debugging-via-ohci1394.txt ieee1394: update URLs in debugging-via-ohci1394.txt 2009-10-03 09:28:11 +02:00
dell_rbu.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
devices.txt Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2010-10-28 09:35:11 -07:00
dmaengine.txt dmaengine: Add API documentation for slave dma usage 2011-05-25 14:49:20 -07:00
dontdiff Documentation: update dontdiff file 2011-05-23 15:14:11 -07:00
dynamic-debug-howto.txt Merge branch 'docs-next' of git://git.lwn.net/linux-2.6 2011-03-27 19:46:59 -07:00
edac.txt Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
eisa.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
email-clients.txt Documentation/email-clients.txt: update Thunderbird docs with wordwrap plugin 2011-01-13 08:03:15 -08:00
feature-removal-schedule.txt Documentation/feature-removal-schedule.txt: remove ns_cgroup from feature-removal-schedule.txt 2011-06-15 20:04:02 -07:00
flexible-arrays.txt flex_array: flex_array_prealloc takes a number of elements, not an end 2011-04-28 16:12:47 -04:00
futex-requeue-pi.txt futex: add requeue-pi documentation 2009-05-09 07:12:50 +02:00
gcov.txt trivial: fix typo in CONFIG_DEBUG_FS in gcov doc 2009-09-21 15:14:56 +02:00
gpio.txt Revert "gpiolib: annotate gpio-intialization with __must_check" 2011-01-13 17:26:46 -08:00
highuid.txt
…
hw_random.txt
…
hwspinlock.txt drivers: hwspinlock: add framework 2011-02-17 09:52:03 -08:00
init.txt init/main.c: improve usability in case of init binary failure 2010-03-06 11:26:29 -08:00
initrd.txt
…
intel_txt.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
io-mapping.txt
…
io_ordering.txt
…
iostats.txt Documentation/iostats.txt: bit-size reference etc. 2011-03-23 20:44:18 +01:00
irqflags-tracing.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
isapnp.txt
…
java.txt
…
kernel-doc-nano-HOWTO.txt docbook: warn on unused doc entries 2010-09-11 16:49:21 -07:00
kernel-docs.txt Documentation: update kernel-docs.txt 2011-01-06 09:59:38 -08:00
kernel-parameters.txt usb-storage: redo incorrect reads 2011-06-07 09:05:42 -07:00
kmemcheck.txt kmemcheck: update documentation 2009-07-01 22:36:22 +02:00
kmemleak.txt Documentation: update kmemleak supported archs 2011-06-15 21:52:50 -07:00
kobject.txt kobject: documentation: Update to refer to kset-example.c. 2010-03-19 07:12:20 -07:00
kprobes.txt tree-wide: fix comment/printk typos 2010-11-01 15:38:34 -04:00
kref.txt kref: Fix typo in kref documentation 2011-03-07 13:20:05 -08:00
ldm.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
local_ops.txt trivial: Miscellaneous documentation typo fixes 2009-06-12 18:01:47 +02:00
lockdep-design.txt lockdep: Fix typos in documentation 2009-08-07 12:03:46 +02:00
lockstat.txt Documentation: Add statistics about nested locks 2011-05-28 17:03:29 +02:00
logo.gif Revert "linux.conf.au 2009: Tuz" 2009-04-27 12:00:27 -07:00
logo.txt Revert "linux.conf.au 2009: Tuz" 2009-04-27 12:00:27 -07:00
magic-number.txt take coda-private headers out of include/linux 2011-01-12 20:02:48 -05:00
mca.txt
…
md.txt md:Documentation/md.txt - fix typo 2011-06-09 11:43:04 +10:00
media-framework.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
memory-barriers.txt smp: Document transitivity for memory barriers. 2011-03-04 08:05:49 -08:00
memory-hotplug.txt memory hotplug: Allow memory blocks to span multiple memory sections 2011-02-03 16:08:57 -08:00
memory.txt Documentation/memory.txt: remove some very outdated recommendations 2009-09-22 07:17:26 -07:00
mono.txt
…
mutex-design.txt mutex: Fix annotations to include it in kernel-locking docbook 2010-09-03 08:19:51 +02:00
nmi_watchdog.txt
…
nommu-mmap.txt nommu: fix malloc performance by adding uninitialized flag 2009-12-15 08:53:24 -08:00
numastat.txt mm: fix NUMA accounting in numastat.txt 2009-09-22 07:17:39 -07:00
oops-tracing.txt panic: Add taint flag TAINT_FIRMWARE_WORKAROUND ('I') 2010-05-19 08:37:43 +01:00
padata.txt Documentation/padata.txt: fix typos etc. 2010-08-11 08:59:18 -07:00
parport-lowlevel.txt
…
parport.txt
…
pi-futex.txt
…
pnp.txt doc: capitalization and other minor fixes in pnp doc 2010-02-05 12:22:44 +01:00
preempt-locking.txt
…
printk-formats.txt Documentation: update printk-formats.txt 2011-06-15 21:52:50 -07:00
prio_tree.txt
…
rbtree.txt Documentation: remove anticipatory scheduler info 2010-11-11 12:09:59 +01:00
rfkill.txt Document the rfkill sysfs ABI 2010-03-10 17:09:33 -05:00
robust-futex-ABI.txt futex: documentation: fix inconsistent description of futex list_op_pending 2009-06-18 13:03:56 -07:00
robust-futexes.txt
…
rt-mutex-design.txt variable name fix to Documentation/rt-mutex-design.txt 2010-06-05 17:39:09 +02:00
rt-mutex.txt
…
rtc.txt RTC: Fix up rtc.txt documentation to reflect changes to generic rtc layer 2011-03-09 11:25:10 -08:00
serial-console.txt
…
sgi-ioc4.txt
…
sgi-visws.txt
…
sparse.txt update email address 2010-07-19 10:56:54 +02:00
spinlocks.txt locking: Remove deprecated lock initializers 2011-01-27 12:30:38 +01:00
stable_api_nonsense.txt doc: stable_api_nonsense.txt: fix paragraph to make more sense. 2011-03-30 12:02:05 +02:00
stable_kernel_rules.txt Documentation: -stable rules: upstream commit ID requirement reworded 2010-04-22 15:24:56 -07:00
svga.txt
…
sysfs-rules.txt Fix typos in comments 2010-03-16 11:47:56 +01:00
sysrq.txt documentation: update sysrq.txt magic sysrq keys 2010-10-26 17:32:41 -07:00
unaligned-memory-access.txt
…
unicode.txt
…
unshare.txt
…
vgaarbiter.txt Documentation: fix vgaarbiter.txt typos etc. 2011-05-23 15:14:11 -07:00
video-output.txt
…
volatile-considered-harmful.txt Documentation/volatile-considered-harmful.txt: correct cpu_relax() documentation 2010-03-24 16:31:20 -07:00
workqueue.txt workqueue: Document debugging tricks 2011-03-31 13:40:42 +02:00
xz.txt decompressors: add XZ decompressor module 2011-01-13 08:03:24 -08:00
zorro.txt
…