kernel/linux.git/Documentation/ABI/testing/sysfs-class-devfreq, branch v6.6.131

PM / devfreq: Fix buffer overflow in trans_stat_show

2024-02-01T00:18:50+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: Greg Kroah-Hartman

PM / devfreq: Remove the invalid description for get_target_freq

2021-04-08T04:14:51+00:00

First of all, no_central_polling was removed since commit 7e6fdd4bad03 ("PM / devfreq: Core updates to support devices which can idle") Secondly, get_target_freq() is not only called only with update_devfreq() notified by OPP now, but also min/max freq qos notifier. So remove this invalid description now to avoid confusing. Signed-off-by: Dong Aisheng Signed-off-by: Chanwoo Choi

Merge tag 'devfreq-next-for-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux

2020-12-11T18:40:00+00:00

Pull devfreq updates for 5.11 from Chanwoo Choi: 1. Update devfreq core - Add new devfreq_frequency tracepoint to show the frequency change information. - Add governor feature flag. The devfreq governor is able to set the specific flag in order to support a non-common feature. For example, if the governor supports the 'immutable' feature, don't allow user space to change the governor via sysfs. - Add governor sysfs attribute flag for each sysfs file. Prior to that the devfreq subsystem allowed all of the sysfs files to be accessed regardless of the governor type. But some sysfs fils are not supported by specific devfreq governors. In order to only allow the sysfs files supported by the governor to be accessed, clarify the access permissions of sysfs attributes according to the governor. When adding the devfreq governor, specify the available attribute information by using DEVFREQ_GOV_ATTR_* symbols. The user can read or write the sysfs attributes in accordance to the specified access permissions. - Clean-up the code to reduce duplication for the devfreq tracepoint and to remove redundant governor_name field from struct devfreq. 2. Update exynos-bus.c devfreq driver - Add interconnect API support to the Samsung Exynos Bus Frequency driver, exynos-bus.c. Complementing the devfreq driver with interconnect functionality allows to ensure that the QoS requirements regarding devices accessing the system memory (e.g. video processing devices) will be met and allows to avoid issues like DMA underrun. 3. Update tegra devfreq driver - Add interconnect support and OPP interface to tegra30-devfreq.c. Also, it is to guarantee the QoS requirement of some devices like the display controller. - Move tegra20-devfreq.c from drivers/devfreq/ into drivers/memory/tegra/ in order to use the more proper monitoring feature such as EMC_STAT which is located in drivers/memory/tegra/. - Separate the configuration information for different SoCs in tegra30-devfrqe.c. The tegra30-devfreq.c had been supporting both tegra30-actmon and tegra124-actmon devices. In order to use the more correct configuration data, separate them. - Use dev_err_probe() to handle the deferred probe error in tegra30-devfreq.c. 4. Pull the request of 'Tegra SoC and clock controller changes for v5.11' sent by Krzysztof Kozlowski in order to avoid a build error." * tag 'devfreq-next-for-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux: PM / devfreq: tegra30: Separate configurations per-SoC generation PM / devfreq: tegra30: Support interconnect and OPPs from device-tree PM / devfreq: tegra20: Deprecate in a favor of emc-stat based driver PM / devfreq: exynos-bus: Add registration of interconnect child device dt-bindings: devfreq: Add documentation for the interconnect properties soc/tegra: fuse: Add stub for tegra_sku_info soc/tegra: fuse: Export tegra_read_ram_code() clk: tegra: Export Tegra20 EMC kernel symbols PM / devfreq: tegra30: Silence deferred probe error PM / devfreq: tegra20: Relax Kconfig dependency PM / devfreq: tegra20: Silence deferred probe error PM / devfreq: Remove redundant governor_name from struct devfreq PM / devfreq: Add governor attribute flag for specifc sysfs nodes PM / devfreq: Add governor feature flag PM / devfreq: Add tracepoint for frequency changes PM / devfreq: Unify frequency change to devfreq_update_target func trace: events: devfreq: Use fixed indentation size to improve readability

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 governor attribute flag for specifc sysfs nodes

2020-10-26T02:46:54+00:00

DEVFREQ supports the default governors like performance, simple_ondemand and also allows the devfreq driver to add their own governor like tegra30-devfreq.c according to their requirement. In result, some sysfs attributes are useful or not useful. Prior to that the user can access all sysfs attributes regardless of the available attributes. So, clarify the access permission of sysfs attributes according to governor. When adding the devfreq governor, can specify the available attribute information by using DEVFREQ_GOV_ATTR_* constant variable. The user can read or write the sysfs attributes in accordance to the specified attributes. When adding the governor, can add the following attributes according to the governor feature. [Definition for speific sysfs attributes] - DEVFREQ_GOV_ATTR_POLLING_INTERVAL to update polling interval for timer. : /sys/class/devfreq/[devfreq dev name]/polling_interval - DEVFREQ_GOV_ATTR_TIMER to change the type of timer on either deferrable or dealyed timer. : /sys/class/devfreq/[devfreq dev name]/timer And all devfreq governors have to support the following common attributes. The common attributes are added to devfreq class by default. - governor - available_governors - available_frequencies - cur_freq - target_freq - min_freq - max_freq - trans_stat [Table of governor attribute flags for devfreq governors] ------------------------------------------------------------------------------ | simple | perfor | power | user | passive | tegra30 | ondemand | mance | save | space| | ------------------------------------------------------------------------------ governor | O | O | O | O | O | O available_governors | O | O | O | O | O | O available_frequencies | O | O | O | O | O | O cur_freq | O | O | O | O | O | O target_freq | O | O | O | O | O | O min_freq | O | O | O | O | O | O max_freq | O | O | O | O | O | O trans_stat | O | O | O | O | O | O -------------------------------------------------------- polling_interval | O | X | X | X | X | O timer | O | X | X | X | X | X ------------------------------------------------------------------------------ Reviewed-by: Dmitry Osipenko Tested-by: Dmitry Osipenko Signed-off-by: Chanwoo Choi

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