Bug 426883

Summary: Please revert smooth brightness transition patch. Epilepsy risk.
Product: [Plasma] Powerdevil Reporter: retired <pepko94>
Component: generalAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED FIXED    
Severity: normal CC: kde, kde, nate
Priority: NOR    
Version: 5.19.90   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In: 5.20.0
Sentry Crash Report:

Description retired 2020-09-22 19:07:51 UTC
So, with 5.20 brightness is meant to transition smoothly. Problem is that not all laptops will do it in a smooth manner, for example my T430 flickers a lot.
It only adds unnecessary delay and makes my laptop seem like it's lagging.

Maybe it looks nice on some "modern" laptops, who knows.

Also it is smoothed out even after idle period, which really makes my laptop feel like it's a laggy pile of crap. And it's not.

I would go as far as suggest that there should be epilepsy warning while logging in to plasma!
Comment 1 Kai Uwe Broulik 2020-09-22 19:15:40 UTC
How many brightness steps does your laptop support? Please provide the output of

$ qdbus org.kde.Solid.PowerManagement /org/kde/Solid/PowerManagement/Actions/BrightnessControl org.kde.Solid.PowerManagement.Actions.BrightnessControl.brightnessMax
Comment 2 Nate Graham 2020-09-23 15:49:03 UTC
Can you add a screen recording showing what it looks like for you?

Either way the correct solution would be to fix the flickering, not revert the feature entirely.
Comment 3 David Edmundson 2020-09-23 16:32:02 UTC
Marking as needs info
Comment 4 retired 2020-09-23 20:21:41 UTC
@Kai Uwe Broulik
15
Comment 5 Bug Janitor Service 2020-10-08 04:33:14 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
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If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 6 Kai Uwe Broulik 2020-10-08 06:50:46 UTC
 I was pretty sure it would not animate for less than a certain amount of steps.
Comment 7 Bug Janitor Service 2020-10-08 19:58:27 UTC
A possibly relevant merge request was started @ https://invent.kde.org/plasma/powerdevil/-/merge_requests/26
Comment 8 Kai Uwe Broulik 2020-10-09 02:52:31 UTC
Git commit 6fd6179b63d17548ae2dc144afa96d86cda5957e by Kai Uwe Broulik.
Committed on 08/10/2020 at 19:55.
Pushed by ngraham into branch 'master'.

Honor animation brightness threshold also for sysfs helper

We should only animate the screen brightness if there are enough steps available
to make for a smooth transition. This check was forgotten for the new sysfs
brightness animation.
FIXED-IN: 5.20.0

M  +6    -0    daemon/backends/upower/backlighthelper.cpp
M  +3    -1    daemon/backends/upower/powerdevilupowerbackend.cpp

https://invent.kde.org/plasma/powerdevil/commit/6fd6179b63d17548ae2dc144afa96d86cda5957e
Comment 9 Nate Graham 2020-10-09 02:53:05 UTC
Git commit 053f92ccd69d851b843bf8d043875fc9b9821379 by Nate Graham, on behalf of Kai Uwe Broulik.
Committed on 09/10/2020 at 02:52.
Pushed by ngraham into branch 'Plasma/5.20'.

Honor animation brightness threshold also for sysfs helper

We should only animate the screen brightness if there are enough steps available
to make for a smooth transition. This check was forgotten for the new sysfs
brightness animation.
FIXED-IN: 5.20.0


(cherry picked from commit 6fd6179b63d17548ae2dc144afa96d86cda5957e)

M  +6    -0    daemon/backends/upower/backlighthelper.cpp
M  +3    -1    daemon/backends/upower/powerdevilupowerbackend.cpp

https://invent.kde.org/plasma/powerdevil/commit/053f92ccd69d851b843bf8d043875fc9b9821379