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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-16 18:10:59 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-16 18:10:59 +0100 |
commit | 2bf16b7a73caf3435f782e4170cfe563675e10f9 (patch) | |
tree | 7f4c5b28a02f08c4d6fd69dd43db5872b07c20c4 /Documentation/trace | |
parent | Merge tag 'driver-core-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel... (diff) | |
parent | VME: Return -EBUSY when DMA list in use (diff) | |
download | linux-2bf16b7a73caf3435f782e4170cfe563675e10f9.tar.xz linux-2bf16b7a73caf3435f782e4170cfe563675e10f9.zip |
Merge tag 'char-misc-4.15-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc updates from Greg KH:
"Here is the big set of char/misc and other driver subsystem patches
for 4.15-rc1.
There are small changes all over here, hyperv driver updates, pcmcia
driver updates, w1 driver updats, vme driver updates, nvmem driver
updates, and lots of other little one-off driver updates as well. The
shortlog has the full details.
All of these have been in linux-next for quite a while with no
reported issues"
* tag 'char-misc-4.15-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (90 commits)
VME: Return -EBUSY when DMA list in use
w1: keep balance of mutex locks and refcnts
MAINTAINERS: Update VME subsystem tree.
nvmem: sunxi-sid: add support for A64/H5's SID controller
nvmem: imx-ocotp: Update module description
nvmem: imx-ocotp: Enable i.MX7D OTP write support
nvmem: imx-ocotp: Add i.MX7D timing write clock setup support
nvmem: imx-ocotp: Move i.MX6 write clock setup to dedicated function
nvmem: imx-ocotp: Add support for banked OTP addressing
nvmem: imx-ocotp: Pass parameters via a struct
nvmem: imx-ocotp: Restrict OTP write to IMX6 processors
nvmem: uniphier: add UniPhier eFuse driver
dt-bindings: nvmem: add description for UniPhier eFuse
nvmem: set nvmem->owner to nvmem->dev->driver->owner if unset
nvmem: qfprom: fix different address space warnings of sparse
nvmem: mtk-efuse: fix different address space warnings of sparse
nvmem: mtk-efuse: use stack for nvmem_config instead of malloc'ing it
nvmem: imx-iim: use stack for nvmem_config instead of malloc'ing it
thunderbolt: tb: fix use after free in tb_activate_pcie_devices
MAINTAINERS: Add git tree for Thunderbolt development
...
Diffstat (limited to 'Documentation/trace')
-rw-r--r-- | Documentation/trace/coresight-cpu-debug.txt | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/Documentation/trace/coresight-cpu-debug.txt b/Documentation/trace/coresight-cpu-debug.txt index b3da1f90b861..2b9b51cd501e 100644 --- a/Documentation/trace/coresight-cpu-debug.txt +++ b/Documentation/trace/coresight-cpu-debug.txt @@ -149,11 +149,23 @@ If you want to limit idle states at boot time, you can use "nohlt" or At the runtime you can disable idle states with below methods: -Set latency request to /dev/cpu_dma_latency to disable all CPUs specific idle -states (if latency = 0uS then disable all idle states): -# echo "what_ever_latency_you_need_in_uS" > /dev/cpu_dma_latency - -Disable specific CPU's specific idle state: +It is possible to disable CPU idle states by way of the PM QoS +subsystem, more specifically by using the "/dev/cpu_dma_latency" +interface (see Documentation/power/pm_qos_interface.txt for more +details). As specified in the PM QoS documentation the requested +parameter will stay in effect until the file descriptor is released. +For example: + +# exec 3<> /dev/cpu_dma_latency; echo 0 >&3 +... +Do some work... +... +# exec 3<>- + +The same can also be done from an application program. + +Disable specific CPU's specific idle state from cpuidle sysfs (see +Documentation/cpuidle/sysfs.txt): # echo 1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state/disable |