Bug 500337

Summary:	External monitor brightness getting reset with ddcutil version prior to 2.2.0
Product:	[Plasma] plasmashell	Reporter:	Kubek4155 <bumblebeepllxd124>
Component:	Power management & brightness	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	RESOLVED UPSTREAM
Severity:	minor	CC:	jpetso, kdedev, nate, tesfabpel
Priority:	NOR
Version First Reported In:	6.3.1
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=494408
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Kubek4155 2025-02-18 19:06:43 UTC

SUMMARY
After an external screen stops receiving data because of power saving settings in Plasma and turns back on, its brightness is always set to 100%. 

STEPS TO REPRODUCE
1. Wait for every screen to black out because of power saving
2. Start using the computer again


SYSTEM INFO:
Linux:  6.13.2-arch1-1
KDE Plasma Version: 6.3.1
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2

ADDITIONAL INFORMATION
I use a laptop with an Intel iGPU and Nvidia RTX 4050, the iGPU is turned off in the laptop's firmware.

Comment 1 tesfabpel 2025-02-19 19:20:13 UTC

It also happens to me with an external monitor via Display Port (it uses ddcutil).

I'm on ArchLinux with Plasma 6.3.1 (like this bug report), ddcutil 2.1.4 (there's 2.2.0 in testing in Arch's repos, I don't know if it improves things).

This is what `ddcutil detect` reports:

```
Display 1
   I2C bus:  /dev/i2c-10
   DRM connector:           card1-DP-1
   EDID synopsis:
      Mfg id:               PHL - Philips Consumer Electronics Company
      Model:                PHL 326M6V
      Product code:         49555  (0xc193)
      Serial number:        
      Binary serial number: [REDACTED]
      Manufacture year:     2019,  Week: 10
   VCP version:         3.0
```

This is what it says before shutting the screen off:
$ ddcutil getvcp 10
VCP code 0x10 (Luminosity                    ): current value =     0, max value =   100

This is after (done via using KDE's power management "Switch the screen off" customizable shortcut):
$ ddcutil getvcp 10
VCP code 0x10 (Luminosity                    ): current value =   100, max value =   100

Comment 2 tesfabpel 2025-02-25 19:19:06 UTC

I've updated my system and now `ddcutil` is at version 2.2.0-1 and the issue seems resolved. Plasma is still at version 6.3.1... Can somebody else confirm it is the case?

Comment 3 TraceyC 2025-02-25 19:26:17 UTC

Duplicate of 495109. Please follow that report for updates. Thanks!

*** This bug has been marked as a duplicate of bug 495109 ***