Bug 470664 - Laptop screen brightness not restored if interrupted while screen-dimming
Summary: Laptop screen brightness not restored if interrupted while screen-dimming
Status: REPORTED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (show other bugs)
Version: 6.2.4
Platform: Fedora RPMs Linux
: NOR minor
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-06-05 12:12 UTC by slartibart70
Modified: 2024-12-18 21:40 UTC (History)
6 users (show)

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Description slartibart70 2023-06-05 12:12:41 UTC
related bug: https://bugs.kde.org/show_bug.cgi?id=470106

I have a 2 monitor setup, integrated laptop screen and dp-4k monitor.
Wait until powerdevil is locking the screen, and, after some time, dimming the (laptop-only) monitor.
Then interrupt by keyboard press.
Login again.

Expectation: 
Laptop screen brightness should be restored to the same level as before.
What happens instead:
The laptop brightness is 'a bit' brighter than previously dimmed, but still way too dark.

My current workaround is to explicitly call brightnessctl with 'my' settings to get the display bright enough again (or use Fn-* keys)


Operating System: Fedora Linux 37
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.9
Kernel Version: 6.3.5-100.fc37.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-7820HQ CPU @ 2.90GHz
Memory: 31,1 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 630
Manufacturer: LENOVO
Product Name: 20J6003DGE
System Version: ThinkPad T470p
Comment 1 slartibart70 2023-06-05 12:13:30 UTC
also related: https://bugs.kde.org/show_bug.cgi?id=470107
Comment 2 Nicolas Fella 2023-06-11 21:09:02 UTC
What do you mean with "Then interrupt by keyboard press. Login again."?
Comment 3 Jakob Petsovits 2024-04-03 11:37:32 UTC
(In reply to Nicolas Fella from comment #2)
> What do you mean with "Then interrupt by keyboard press. Login again."?

My reading is that this describes the interaction on the lock screen. Keyboard press will (attempt to) cancel the dimming and show the password field. "Login again" refers to unlocking the session, as opposed to anything SDDM-related.

Note that dimming has seen a number of improvements since 5.27.5, in particular:
* https://invent.kde.org/plasma/powerdevil/-/commit/14647dc6ffd1104c1c0ab393518de8a65cb39d70 (went into 5.27.8)
* https://invent.kde.org/plasma/powerdevil/-/commit/8681355217eb6ff121785572eaf4ef2ca21b464b (went into 6.0.1).
The dimming code is still a little fragile in its interactions with other brightness mechanisms, but it's possible that this particular bug has been fixed by now.

Could you retest with a more recent Plasma (5.27.8 or higher, ideally Plasma 6.0.2 or higher) and report back on whether you're still seeing this issue?
Comment 4 Marcus Johansson 2024-04-03 17:12:27 UTC
I can confirm this still happening on plasma 6.0.3.

Forum post here: https://discuss.kde.org/t/night-colors-brightness-and-screen-saver/12285

Since there is no way of triggering this other than randomly catching my computer "dimming" it's hard to provide much more than "it still happens".

But if you have ideas of what I could provide that could help, please let me know.
Comment 5 Jakob Petsovits 2024-12-16 17:56:04 UTC
Hi, quick update.

In Plasma 6.2, KWin/Wayland plays a role in (re)setting display brightness. PowerDevil is still responsible for changing brightness values, but KWin will issue commands to set the brightness that it stored.

In Plasma 6.3, we've merged a substantial refactoring of dimming logic. Under Wayland, this means the configured brightness will never be permanently lowered to a dimmed value accidentally. Any dimming is temporary and will be reset to the current brightness value at the next KWin output configuration change event. Under X11, also more robust, but didn't solve the case where the display is still dimmed after having rebooted with dimming on. See merge requests https://invent.kde.org/plasma/powerdevil/-/merge_requests/466 and https://invent.kde.org/plasma/powerdevil/-/merge_requests/469 for code & more information on this.

Altogether, there's a good chance that this bug was fixed either in a released Plasma version already or will be fixed in 6.3. I can't confirm the originally reported issue, please keep us up to date now or after 6.3 is available for your system. Thanks!