linux-stable.git/drivers/leds/led-core.c, branch linux-5.2.y

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

leds: avoid flush_work in atomic context

2019-05-31T20:29:14+00:00

It turns out that various triggers use led_blink_setup() from atomic
context, so we can't do a flush_work there. Flush is still needed for
slow LEDs, but we can move it to sysfs code where it is safe.

    WARNING: inconsistent lock state
    5.2.0-rc1 #1 Tainted: G        W
    --------------------------------
    inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
    swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
    000000006e30541b
    ((work_completion)(&led_cdev->set_brightness_work)){+.?.}, at:
    +__flush_work+0x3b/0x38a
    {SOFTIRQ-ON-W} state was registered at:
      lock_acquire+0x146/0x1a1
     __flush_work+0x5b/0x38a
     flush_work+0xb/0xd
     led_blink_setup+0x1e/0xd3
     led_blink_set+0x3f/0x44
     tpt_trig_timer+0xdb/0x106
     ieee80211_mod_tpt_led_trig+0xed/0x112

Fixes: 0db37915d912 ("leds: avoid races with workqueue")
Signed-off-by: Pavel Machek 
Tested-by: Hugh Dickins 
Signed-off-by: Jacek Anaszewski

leds: avoid races with workqueue

2019-05-02T20:54:51+00:00

There are races between "main" thread and workqueue. They manifest
themselves on Thinkpad X60:

This should result in LED blinking, but it turns it off instead:

    root@amd:/data/pavel# cd /sys/class/leds/tpacpi\:\:power
    root@amd:/sys/class/leds/tpacpi::power# echo timer > trigger
    root@amd:/sys/class/leds/tpacpi::power# echo timer > trigger

It should be possible to transition from blinking to solid on by echo
0 > brightness; echo 1 > brightness... but that does not work, either,
if done too quickly.

Synchronization of the workqueue fixes both.

Fixes: 1afcadfcd184 ("leds: core: Use set_brightness_work for the blocking op")
Signed-off-by: Pavel Machek 
Signed-off-by: Jacek Anaszewski

leds: Add helper for getting default pattern from Device Tree

2019-01-16T21:08:07+00:00

Multiple LED triggers might need to access default pattern so add a
helper for that.

Signed-off-by: Krzysztof Kozlowski 
Acked-by: Pavel Machek 
Signed-off-by: Jacek Anaszewski

leds: core: Fix regression caused by commit 2b83ff96f51d

2018-01-07T12:27:07+00:00

Commit 2b83ff96f51d ("led: core: Fix brightness setting when setting delay_off=0")
replaced del_timer_sync(&led_cdev->blink_timer) with led_stop_software_blink()
in led_blink_set(), which additionally clears LED_BLINK_SW flag as well as
zeroes blink_delay_on and blink_delay_off properties of the struct led_classdev.

Cleansing of the latter ones wasn't required to fix the original issue but
wasn't considered harmful. It nonetheless turned out to be so in case when
pointer to one or both props is passed to led_blink_set() like in the
ledtrig-timer.c. In such cases zeroes are passed later in delay_on and/or
delay_off arguments to led_blink_setup(), which results either in stopping
the software blinking or setting blinking frequency always to 1Hz.

Avoid using led_stop_software_blink() and add a single call required
to clear LED_BLINK_SW flag, which was the only needed modification to
fix the original issue.

Fixes 2b83ff96f51d ("led: core: Fix brightness setting when setting delay_off=0")
Signed-off-by: Jacek Anaszewski

led: core: Fix brightness setting when setting delay_off=0

2017-12-27T19:45:07+00:00

With the current code, the following sequence won't work :
echo timer > trigger

echo 0 >  delay_off
* at this point we call
** led_delay_off_store
** led_blink_set
*** stop timer
** led_blink_setup
** led_set_software_blink
*** if !delay_on, led off
*** if !delay_off, set led_set_brightness_nosleep <--- LED_BLINK_SW is set but timer is stop
*** otherwise start timer/set LED_BLINK_SW flag

echo xxx > brightness
* led_set_brightness
** if LED_BLINK_SW
*** if brightness=0, led off
*** else apply brightness if next timer <--- timer is stop, and will never apply new setting
** otherwise set led_set_brightness_nosleep

To fix that, when we delete the timer, we should clear LED_BLINK_SW.

Cc: linux-leds@vger.kernel.org
Signed-off-by: Matthieu CASTET 
Signed-off-by: Jacek Anaszewski

leds: Convert timers to use timer_setup()

2017-10-25T19:52:22+00:00

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Richard Purdie 
Cc: Pavel Machek 
Cc: Willy Tarreau 
Cc: linux-leds@vger.kernel.org
Signed-off-by: Kees Cook 
Signed-off-by: Jacek Anaszewski

led: core: Fix blink_brightness setting race

2016-11-22T11:07:05+00:00

All 3 of led_timer_func, led_set_brightness and led_set_software_blink
set blink_brightness. If led_timer_func or led_set_software_blink race
with led_set_brightness they may end up overwriting the new
blink_brightness. The new atomic work_flags does not protect against
this as it just protects the flags and not blink_brightness.

This commit introduces a new new_blink_brightness value which gets
set by led_set_brightness and read by led_timer_func on LED on, fixing
this.

Dealing with the new brightness at LED on time, makes the new
brightness apply sooner, which also fixes a led_set_brightness which
happens while a oneshot blink which ends in LED on is running not
getting applied.

Signed-off-by: Hans de Goede 
Signed-off-by: Jacek Anaszewski

led: core: Use atomic bit-field for the blink-flags

2016-11-22T11:07:05+00:00

All the LED_BLINK* flags are accessed read-modify-write from e.g.
led_set_brightness and led_blink_set_oneshot while both
set_brightness_work and the blink_timer may be running.

If these race then the modify step done by one of them may be lost,
switch the LED_BLINK* flags to a new atomic work_flags bit-field
to avoid this race.

Signed-off-by: Hans de Goede 
Signed-off-by: Jacek Anaszewski

leds: core: Fix brightness setting upon hardware blinking enabled

2016-06-08T09:47:06+00:00

Commit 76931edd54f8 ("leds: fix brightness changing when software blinking
is active") changed the semantics of led_set_brightness() which according
to the documentation should disable blinking upon any brightness setting.
Moreover it made it different for soft blink case, where it was possible
to change blink brightness, and for hardware blink case, where setting
any brightness greater than 0 was ignored.

While the change itself is against the documentation claims, it was driven
also by the fact that timer trigger remained active after turning blinking
off. Fixing that would have required major refactoring in the led-core,
led-class, and led-triggers because of cyclic dependencies.

Finally, it has been decided that allowing for brightness change during
blinking is beneficial as it can be accomplished without disturbing
blink rhythm.

The change in brightness setting semantics will not affect existing
LED class drivers that implement blink_set op thanks to the LED_BLINK_SW
flag introduced by this patch. The flag state will be from now on checked
in led_set_brightness() which will allow to distinguish between software
and hardware blink mode. In the latter case the control will be passed
directly to the drivers which apply their semantics on brightness set,
which is disable the blinking in case of most such drivers. New drivers
will apply new semantics and just change the brightness while hardware
blinking is on, if possible.

The issue was smuggled by subsequent LED core improvements, which modified
the code that originally introduced the problem.

Fixes: f1e80c07416a ("leds: core: Add two new LED_BLINK_ flags")
Signed-off-by: Tony Makkiel 
Signed-off-by: Jacek Anaszewski