New underflow of regulator enable count warnings in v5.0-rc1

regulator-dummy: Underflow of regulator enable count

Are these bogus warnings for dummy regulator or do we have real unpaired regulator calls or somewhere?

Hi,

Looks like commit 5451781dadf8 ("regulator: core: Only count load for enabled consumers") started showing new warnings with v5.0-rc cycle:

regulator-dummy: Underflow of regulator enable count

I'm seeing this at least with my pwm-vibra test case:

# rumble-test /dev/input/by-path/platform-vibrator-event 0xffff
pwm-vibrator vibrator: vibrator supply vcc not found, using dummy regulator
input: pwm-vibrator as /devices/platform/vibrator/input/input4
regulator-dummy: Underflow of regulator enable count
Upload rumble effect... id=0
regulator-dummy: Underflow of regulator enable count

Are these bogus warnings for dummy regulator or do we have real unpaired regulator calls or somewhere?

- We can (and will) spit errors out for code that used to be invalid but was never caught before. Specifically if someone leaves a regulator enabled and calls regulator_put() we'll yell. We'll also yell if a single consumer calls more disables than enables.

Hi,

Quoted 17 lines · Tony Lindgren

Hi,

Looks like commit 5451781dadf8 ("regulator: core: Only count load for enabled consumers") started showing new warnings with v5.0-rc cycle:

regulator-dummy: Underflow of regulator enable count

I'm seeing this at least with my pwm-vibra test case:

# rumble-test /dev/input/by-path/platform-vibrator-event 0xffff
pwm-vibrator vibrator: vibrator supply vcc not found, using dummy regulator
input: pwm-vibrator as /devices/platform/vibrator/input/input4
regulator-dummy: Underflow of regulator enable count
Upload rumble effect... id=0
regulator-dummy: Underflow of regulator enable count

Quoted 2 lines

Are these bogus warnings for dummy regulator or do we have real unpaired regulator calls or somewhere?

My first guess is that there's a real unpaired regulator call somewhere.

I actually meant to include this in the commit message, but I'm an idiot and I used "--" to break up the parts of the commit message which confused git when Mark applied it. Sigh. For the full commit message, see:

https://lkml.kernel.org/r/[email protected]

Quoted 4 lines · In that message I

- We can (and will) spit errors out for code that used to be invalid but was never caught before. Specifically if someone leaves a regulator enabled and calls regulator_put() we'll yell. We'll also yell if a single consumer calls more disables than enables.

Looking quickly at 'pwm-vibra.c' it wouldn't surprise me at all if you call regulator_disable() more times than regulator_enable(). If that's true it should be fixed.

OK. Let's see if Sebastian spots where pwm_vibrator_start() and pwm_vibrator_stop() might get called multiple times or something similar.

Quoted 3 lines · Tony Lindgren

OK. Let's see if Sebastian spots where pwm_vibrator_start() and pwm_vibrator_stop() might get called multiple times or something similar.

Given that nobody has noticed that the driver stops working entirely it's possible that the pattern is something like:

pwm_vibrator_start()
pwm_vibrator_stop()
pwm_vibrator_stop()
pwm_vibrator_start()

so it's a temporary underflow that gets corrected (or it could be that not many people are using mainline kernels on these systems). On your system it's the dummy driver but presumably some other users have it connected to actual regulators.

Looks like commit 5451781dadf8 ("regulator: core: Only count load for enabled consumers") started showing new warnings with v5.0-rc cycle:

regulator-dummy: Underflow of regulator enable count

I'm seeing this at least with my pwm-vibra test case:

# rumble-test /dev/input/by-path/platform-vibrator-event 0xffff
pwm-vibrator vibrator: vibrator supply vcc not found, using dummy regulator
input: pwm-vibrator as /devices/platform/vibrator/input/input4
regulator-dummy: Underflow of regulator enable count
Upload rumble effect... id=0
regulator-dummy: Underflow of regulator enable count

Are these bogus warnings for dummy regulator or do we have real unpaired regulator calls or somewhere?

Hi,

Quoted 14 lines · Tony Lindgren

Looks like commit 5451781dadf8 ("regulator: core: Only count load for enabled consumers") started showing new warnings with v5.0-rc cycle:

regulator-dummy: Underflow of regulator enable count

I'm seeing this at least with my pwm-vibra test case:

# rumble-test /dev/input/by-path/platform-vibrator-event 0xffff
pwm-vibrator vibrator: vibrator supply vcc not found, using dummy regulator
input: pwm-vibrator as /devices/platform/vibrator/input/input4
regulator-dummy: Underflow of regulator enable count
Upload rumble effect... id=0
regulator-dummy: Underflow of regulator enable count

Quoted 2 lines

Are these bogus warnings for dummy regulator or do we have real unpaired regulator calls or somewhere?

There are real unpaired regulator calls in the pwm-vibrator driver, that I did not notice when I wrote the driver :(. Good news is, that Paweł Chmiel and Jonathan Bakker are already working on fixing my mess:

https://lore.kernel.org/patchwork/patch/1032759/

On Droid 4 it's a dummy regulator, since I did not know what regulator is being used to supply the vibrator. Probably directly from the battery.