Light transitions from and to 0% no longer work

[AndySymons]

The problem

It used to be the case that a light could be faded up from 0 to 100% and down from 100% to 0% with a transition of any length (my test case is 20 seconds). That is no longer the case. The transition time is now ignored if the start or end brightness is 0%. It still works for fades from and to 1% (with light.turn_on in both cases). With light.turn_off, the transition time is now always ignored. (I assume light.turn_off should be the same as light.turn_on with an end brightness of 0%)

The only workaround appears to be to first turn on at 1% (with no transition) and then do the fade up from 1 to 100%. Conversely one must fade down to 1% (using light.turn_on) and then separately turn off (with no transition).

After this fade down procedure, turning on the light manually will set it to 1%, so it is furthermore necessary to introduce a light profiles file to restore the default to 100%.

The workaround is unnecessarily complicated! Please restore the situation that transitions are always heeded between all percentages (or their value equivalent) including 0%.

What version of Home Assistant Core has the issue?

2024.6.3

What was the last working version of Home Assistant Core?

See additional information below

What type of installation are you running?

Home Assistant OS

Integration causing the issue

light.turn_on (and light.turn_off) service call

Link to integration documentation on our website

No response

Diagnostics information

None. My results are from experimentation with Developer Tools / Services

Example YAML snippet

service: light.turn_on
target:
  entity_id:
    - light.hall_ceiling_light
data:
  transition: 20
  brightness_pct: 0

Anything in the logs that might be useful for us?

No

Additional information

(Edit 29-Jun):

• In 2024.5.3 slow fade up from and down to 0% still worked OK.
• In 2024.5.4 and 2024.5.5, slow fade up from 0% works but slow fade down to 0% does not.

[TheJulianJES]

Which integration provides the light.hall_ceiling_light light?

[AndySymons]

ZHA Philips Hue White lights and a MOES Smart ZigBee Dimmer Switch Module. My results with previous OS versions a few weeks ago were with the same lights.

Update: I am now finding that I cannot go from 0% to 1% either - the light goes straight to 100%. So the proposed workaround -- to go from 0 to 1 and then 1 to 100 -- is also not possible. Only if I fade from another value DOWN to 1% (with any transition time) can I then fade properly (with 20s transition time) from 1% to 100%. Most perplexing.

[nsvrana]

I am experiencing this with Nanoleaf Essentials lights over Thread, they are new so I thought it was something about the integration.

[AndySymons]

The issue appears to be fixed in 2024.6.4 😀 Thanks! 👏

[AndySymons]

... but it is broken again in 2024.7.0 !! 😔

It is back to the condition that it fades correctly from and to 1%, but not 0%. A transition from 0 to 1% also does not work (it goes to 100% instead).

So I reverted to 2024.6.4 and now it does not work with that release either! Now I am very confused. Could there be something else in my configuration that affects this? For example, the one that works with 2024.6.4 is a container installation and the one that fails is Hass.

Transitions are quite a fundamental service of HA. So can we get this fixed (permanently)?

[AndySymons]

UPDATE 8 July. Further trial and error shows that the light_profiles.csv file affects the problem. I now have HA 2024.7.1 (HASS) installed.

In light_profiles.csv I have

id,x,y,brightness,transition
group.all_lights.default,0.41334,0.43663,255,0

... because I want the dimmable lights to perform like non-dimmable lights when no transition is specified. The colour values are just dummies as I only use white lights.

I am still testing simply using Developer Tools --> Services. I have now established that when the light_profiles.csv file is there, light.turn_on always uses the 'default' value and ignores the specified transition. I proved this by trying different values for the transition in the light_profiles.csv file.

If I delete the light_profiles.csv file, there is a small improvement:

1. I can now fade from 0 to 100% correctly
2. I can now turn on from 0 to 1% correctly
3. Fade down to 1% still works
4. Fade down to 0% is still incorrect

... plus, of course, the fact that without the light_profiles.csv file, I cannot set my default transition.

@TheJulianJES Is there any activity on this issue? From where I am sitting it seems fundamental and easy to reproduce; however since only one other member has responded to this issue report, I still wonder if there is something funny about my system setup.

Please: a) Tell me if you have reproduced it b) If not, tell me what experiments I can carry out to track down the source of the problem on my systems

Cheers.

[fire1ce]

+1 on the issue. turn on with "transition" immediately turns on the light. if the light set to "on" with brightness 1 the transition will work. using ha, z2m, mosquito and node-red.

[fire1ce]

tested the "transition" from home-assistant dev tools with same result. btw, it worked find before, with same settings and same hardware.

[westerlind]

I have this same problem too, but only since around 2 days ago or so, which is around when I installed 2024.7.3, but I'm not sure if this problem started exactly when I updated or maybe one or two days after the update.

I'm wondering if it might be related to something that changed on the Hue side of things, rather than in Home Assistant? (or maybe a combination)

In their release notes at https://www.philips-hue.com/en-us/support/release-notes/bridge there is an entry for the update that was released on July 11 that says Resolved a Matter interoperability issue that may occasionally cause lights on low brightness to turn to full brightness., which seems to be quite close to what we are experiencing here, even if it's not the same. My issue did of course show up after they released that update, and Matter is not involved, but it still seems possible that they might be changing things around related to fading the lights that might cause problems in other situations too.

This might at least be something to keep in mind while looking into this issue.

[TheJulianJES]

This action was provided in the example/OP:

service: light.turn_on
target:
  entity_id:
    - light.hall_ceiling_light
data:
  transition: 20
  brightness_pct: 0

light.turn_on with brightness_pct: 0 will never turn on the light, regardless of the transition. The brightness target is 0, so off.

My Philips Hue lights, connected with ZHA, support turn_off with a transition just fine. Turning them on to 1% brightness with a transition also works as expected. Running HA Core 2024.8.0.dev202407140224, but I don't think there were any changes that should affect this. Still, might be worth trying the beta starting on 31/07/24. ZHA had major changes, but the underlying light code should have been untouched mostly. We also didn't have any changes regarding transitions in ZHA in the last couple major HA releases.

Generally, the service call arguments are mostly passed to the integration that then deals with them. light_profiles.csv are frozen at the moment, as it's a very old concept. There won't be any changes to them. I don't think they should affect this, but I'm not sure. They're likely not tested very much and I'd not use them.

Also, with ZHA, are you targeting individual lights or ZHA groups?

And for reference, these are my ZHA settings:

[westerlind]

I didn't realise this first, but I have 2 Hue lights connected with ZHA which I didn't test earlier, and it turns out that there are problems like this both with those ZHA connected lights and the Hue Bridge connected lights (which is most of my lights).

So I guess that has to mean that there is a problem somewhere else than in the integrations, as it happens with more than one integration?

As long as I don't specify anything else than that I want to turn on or off the lights in my automation, it works perfectly with a short fade, but as soon as I specify anything else, whether that is the actual fading time or the brightness I want to set the lights to, it all breaks down and doesn't work as it should. It either turns on/off right away without a fade, or it sometimes even waits a while (not the same time I specified for the fade) and then turns off without a fade (I have only seen the last one on ZHA). If I don't turn the lights on/off, there are no problems with changing the other options (at least nothing I have noticed).

[westerlind]

This seems to be related to issue #122165

The suggestion from that issue to remove "effect: None" from all scenes (which is added automatically when editing scenes from the GUI, so this has to be done again when scenes are edited in the GUI) made this work again in most of my normal use, but the problem still happens when trying to turn a light on and set a specific fading time if it's not done by activating a scene.

Same thing for ZHA and Hue Bridge connected lights.

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