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| author | Breno Leitao <leitao@debian.org> | 2026-08-05 07:52:36 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-08-10 11:47:20 -1000 |
| commit | a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 (patch) | |
| tree | 39f5b258386e1127d253d293194e9a2991bf3c34 /Documentation/ABI/testing/sysfs-class-led | |
| download | linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.tar.gz linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.zip | |
workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted
apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.
No functional change: only unbound workqueues reach apply_wqattrs_*()
today.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-led')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-led | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led new file mode 100644 index 000000000..d4c918cc1 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led @@ -0,0 +1,89 @@ +What: /sys/class/leds/<led>/brightness +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie <rpurdie@rpsys.net> +Description: + Set the brightness of the LED. + + Most LEDs don't have hardware brightness support, so will + just be turned on for non-zero brightness settings. + + .. Note:: + + For multicolor LEDs, writing to this file will update all + LEDs within the group to a calculated percentage of what + each color LED intensity is set to. + + The percentage is calculated for each grouped LED via + the equation below:: + + led_brightness = brightness * multi_intensity/max_brightness + + For additional details please refer to + Documentation/leds/leds-class-multicolor.rst. + + The value is between 0 and /sys/class/leds/<led>/max_brightness + and is represented by as a decimal. + + Writing 0 to this file clears active trigger. + + Writing non-zero to this file while trigger is active changes the + top brightness trigger is going to use. + + + +What: /sys/class/leds/<led>/max_brightness +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie <rpurdie@rpsys.net> +Description: + Maximum brightness level for this LED, default is 255 (LED_FULL). + + If the LED does not support different brightness levels, this + should be 1. + +What: /sys/class/leds/<led>/brightness_hw_changed +Date: January 2017 +KernelVersion: 4.11 +Description: + Last hardware set brightness level for this LED. Some LEDs + may be changed autonomously by hardware/firmware. Only LEDs + where this happens and the driver can detect this, will have + this file. + + This file supports poll() to detect when the hardware changes + the brightness. + + Reading this file will return the last brightness level set + by the hardware, this may be different from the current + brightness. Reading this file when no hw brightness change + event has happened will return an ENODATA error. + +What: /sys/class/leds/<led>/trigger +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie <rpurdie@rpsys.net> +Description: + Set the trigger for this LED. A trigger is a kernel based source + of LED events. + + You can change triggers in a similar manner to the way an IO + scheduler is chosen. Trigger specific parameters can appear in + /sys/class/leds/<led> once a given trigger is selected. For + their documentation see `sysfs-class-led-trigger-*`. + + Writing "none" removes the trigger for this LED. + + Writing "default" sets the trigger to the LED's default trigger + (which would often be configured in the device tree for the + hardware). + +What: /sys/class/leds/<led>/inverted +Date: January 2011 +KernelVersion: 2.6.38 +Contact: Richard Purdie <rpurdie@rpsys.net> +Description: + Invert the LED on/off state. This parameter is specific to + gpio and backlight triggers. In case of the backlight trigger, + it is useful when driving a LED which is intended to indicate + a device in a standby like state. |
