kernel/linux.git/Documentation/ABI/testing/sysfs-class-devfreq, branch v5.10.257

PM / devfreq: Fix buffer overflow in trans_stat_show

2024-05-02T14:23:44+00:00

commit 08e23d05fa6dc4fc13da0ccf09defdd4bbc92ff4 upstream. Fix buffer overflow in trans_stat_show(). Convert simple snprintf to the more secure scnprintf with size of PAGE_SIZE. Add condition checking if we are exceeding PAGE_SIZE and exit early from loop. Also add at the end a warning that we exceeded PAGE_SIZE and that stats is disabled. Return -EFBIG in the case where we don't have enough space to write the full transition table. Also document in the ABI that this function can return -EFBIG error. Link: https://lore.kernel.org/all/20231024183016.14648-2-ansuelsmth@gmail.com/ Cc: stable@vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218041 Fixes: e552bbaf5b98 ("PM / devfreq: Add sysfs node for representing frequency transition information.") Signed-off-by: Christian Marangi Signed-off-by: Chanwoo Choi Signed-off-by: Sasha Levin Signed-off-by: Jan Kiszka Signed-off-by: Greg Kroah-Hartman

docs: ABI: fix syntax to be parsed using ReST notation

2020-10-30T12:12:39+00:00

There are a number of new changes at the ABI files that cause them to produce warnings when generating ABI output. Fix them. Acked-by: Jonathan Corbet Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/55a89f423cf122982c462d257722e44d6ece4b36.1604042072.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Add support delayed timer for polling mode

2020-07-30T08:22:57+00:00

Until now, the devfreq driver using polling mode like simple_ondemand governor have used only deferrable timer for reducing the redundant power consumption. It reduces the CPU wake-up from idle due to polling mode which check the status of Non-CPU device. But, it has a problem for Non-CPU device like DMC device with DMA operation. Some Non-CPU device need to do monitor continuously regardless of CPU state in order to decide the proper next status of Non-CPU device. So, add support the delayed timer for polling mode to support the repetitive monitoring. The devfreq driver and user can select the kind of timer on either deferrable and delayed timer. For example, change the timer type of DMC device based on Exynos5422-based Odroid-XU3 as following: - If want to use deferrable timer as following: echo deferrable > /sys/class/devfreq/10c20000.memory-controller/timer - If want to use delayed timer as following: echo delayed > /sys/class/devfreq/10c20000.memory-controller/timer Reviewed-by: Bartlomiej Zolnierkiewicz Reviewed-by: Lukasz Luba Signed-off-by: Chanwoo Choi

PM / devfreq: Add clearing transitions stats

2019-12-30T00:59:05+00:00

Add clearing transition table and time in states devfreq statistics by writing 0 (zero) to trans_stat file in devfreq sysfs. An example use is like following: echo 0 > /sys/class/devfreq/devfreqX/trans_stat Signed-off-by: Kamil Konieczny [cw00.choi: Edit return value if entering the wrong value for reset and use arrary3_size() to get the size of 3-dimensional array] Signed-off-by: Chanwoo Choi

PM / devfreq: Add new name attribute for sysfs

2019-12-30T00:59:05+00:00

The commit 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs") changed the node name to devfreq(x). After this commit, it is not possible to get the device name through /sys/class/devfreq/devfreq(X)/*. Add new name attribute in order to get device name. Cc: stable@vger.kernel.org Fixes: 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs") Signed-off-by: Chanwoo Choi

ABI: fix some syntax issues at the ABI database

2019-06-14T16:17:11+00:00

On those three files, the ABI representation described at README are violated. - at sysfs-bus-iio-proximity-as3935: a ':' character is missing after "What" - at sysfs-class-devfreq: there's a typo at Description - at sysfs-class-cxl, it is using the ":" character at a file preamble, causing it to be misinterpreted as a tag. - On the other files, instead of "What", they use "Where". Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Mauro Carvalho Chehab Acked-by: Rafael J. Wysocki Acked-by: Andrew Donnellan # cxl Signed-off-by: Greg Kroah-Hartman

PM / devfreq: add comments and Documentation

2013-06-03T11:20:29+00:00

- Added missing ABI documents - Added comments to clarify the objectives of functions Signed-off-by: MyungJoo Ham Acked-by: Nishanth Menon Acked-by: Rajagopal Venkat

PM / devfreq: Add sysfs node to expose available governors

2012-11-20T09:46:24+00:00

Now that governor list can be variable, knowing the available governors is useful to be able to select a governor using relevant sysfs node. Cc: Rajagopal Venkat Cc: MyungJoo Ham Cc: Kyungmin Park Cc: "Rafael J. Wysocki" Cc: Kevin Hilman Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon Signed-off-by: MyungJoo Ham

PM / devfreq: allow sysfs governor node to switch governor

2012-11-20T09:46:23+00:00

This allows us to select governor runtime from the default configuration without having to rebuild kernel or the devfreq driver using the sysfs node: /sys/class/devfreq/.../governor cat of the governor will return valid governor and an echo 'governor_name'>governor will switch governor Cc: Rajagopal Venkat Cc: MyungJoo Ham Cc: Kyungmin Park Cc: "Rafael J. Wysocki" Cc: Kevin Hilman Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon Acked-by: MyungJoo Ham Signed-off-by: MyungJoo Ham

PM / devfreq: Add sysfs node for representing frequency transition information.

2012-11-20T07:05:44+00:00

This patch adds sysfs node which can be used to get information of frequency transition. It represents transition table which contains total number of transition of each freqeuncy state and time spent. It is inspired CPUFREQ's status driver. Signed-off-by: Jonghwa Lee [Added Documentation/ABI entry, updated kernel-doc, and resolved merge conflict] Signed-off-by: MyungJoo Ham