Bug 500337 - External monitor brightness getting reset with ddcutil version prior to 2.2.0
Summary: External monitor brightness getting reset with ddcutil version prior to 2.2.0
Status: RESOLVED UPSTREAM
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (show other bugs)
Version: 6.3.1
Platform: Arch Linux Linux
: NOR minor
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-02-18 19:06 UTC by Kubek4155
Modified: 2025-02-28 17:38 UTC (History)
4 users (show)

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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 ***