SUMMARY STEPS TO REPRODUCE 1. Login to your account 2. Experience super slow login 3. After looking in the logs what's the issue, powerdevil seems to take long time to start due to timeout with dccutil execution OBSERVED RESULT Login after password successful takes around 15seconds to get to the fully functional desktop Result of the command $ time systemctl --user restart plasma-powerdevil.service real 0m12,568s user 0m0,000s sys 0m0,004s EXPECTED RESULT Login in 2 seconds SOFTWARE/OS VERSIONS Linux/KDE Plasma: Kubuntu 25.04 KDE Plasma Version: 6.3.4 KDE Frameworks Version: 6.12.0 Qt Version: 6.8.3 ADDITIONAL INFORMATION Summary KDE Powerdevil service takes 13+ seconds to start instead of <1 second, causing significant login delays after a recent libddcutil upgrade in Kubuntu 25.04. Environment OS: Kubuntu 25.04 (Plucky Pufferfish) KDE Plasma: 6.3.4 Powerdevil: 4:6.3.4-0ubuntu1 libddcutil: 2.2.0-1 (upgraded from libddcutil4 1.4.1-1build2) Hardware: AMD Ryzen 9 5900X, AMD RX 6700 XT (16GB VRAM) Monitors: 2x ASUS ROG displays via DisplayPort ASUS ROG PG278QR (2016, Week 43) ASUS ROG PG279Q (2016, Week 2) Timeline of Issue October 7, 2024: Initial installation with libddcutil4 1.4.1 - working normally July 6, 2025: libddcutil4 removed during system update - problems began July 22, 2025: Investigation revealed the regression Problem Description After the July 6, 2025 update that removed libddcutil4 and later installation of libddcutil5 2.2.0-1, powerdevil consistently takes 13+ seconds to initialize, causing significant delays during login. Root Cause Analysis Powerdevil service logs show libddcutil spending excessive time communicating with monitors via DDC/CI: jui 22 08:20:53 mauro-amd org_kde_powerdevil[2723]: Starting libddcutil. library built Feb 22 2025 at 15:37:45 jui 22 08:20:53 mauro-amd org_kde_powerdevil[2723]: Initializing libddcutil. ddcutil version: 2.2.0-dev jui 22 08:20:55 mauro-amd org_kde_powerdevil[2723]: busno=9, sleep-multiplier= 2,00, Testing for unsupported feature 0xdd returned Error_Info[DDCRC_RETRIES jui 22 08:20:55 mauro-amd org_kde_powerdevil[2723]: Turning off dynamic sleep and retrying jui 22 08:20:56 mauro-amd org_kde_powerdevil[2723]: busno=9, sleep-multiplier = 1,00, Retesting for unsupported feature 0xdd [...pattern repeats for ~13 seconds across bus 9 and 10...] jui 22 08:21:06 mauro-amd org_kde_powerdevil[2723]: Library initialization complete. Performance Comparison DDC/CI detection times: HDMI connection: 1.6 seconds (normal) DisplayPort connection: 6.7+ seconds (problematic) Manual ddcutil testing: $ ddcutil detect --sleep-multiplier 0.3 --disable-dynamic-sleep Display 1 I2C bus: /dev/i2c-9 DRM connector: card1-DP-1 Model: ROG PG278QR [Completes in ~3 seconds] Display 2 I2C bus: /dev/i2c-10 DRM connector: card1-DP-2 Model: ROG PG279Q [Completes in ~3 seconds] System Logs Evidence Package change history: $ grep "ddcutil" /var/log/dpkg.log* /var/log/dpkg.log:2025-07-06 09:10:36 remove libddcutil4:amd64 1.4.1-1build2 <none> /var/log/dpkg.log:2025-07-06 09:10:36 status not-installed libddcutil4:amd64 <none> /var/log/dpkg.log:2025-07-22 09:55:26 install ddcutil:amd64 <none> 2.2.0-1 Current package versions: $ dpkg -l | grep -E "(ddcutil|powerdevil)" ii ddcutil 2.2.0-1 amd64 Control monitor settings ii libddcutil5:amd64 2.2.0-1 amd64 Control monitor settings - shared library ii libpowerdevilcore2:amd64 4:6.3.4-0ubuntu1 amd64 shared library for KDE power management ii powerdevil 4:6.3.4-0ubuntu1 amd64 KDE power management service for Plasma I/O errors in system logs: jui 22 10:35:17 mauro-amd fwupd[7971]: failed to add device card1-DP-1/drm_dp_aux0: failed to read device firmware header: failed to write 7 bytes to 14: Erreur d'entree/sortie jui 22 10:35:17 mauro-amd fwupd[7971]: failed to add device card1-DP-2/drm_dp_aux1: failed to read device firmware header: failed to write 7 bytes to 14: Erreur d'entree/sortie Analysis and Evidence Hardware is not the issue: Identical symptoms appearing simultaneously on two different monitor models with different manufacturing dates is statistically improbable DisplayPort vs HDMI: DDC/CI works significantly faster on HDMI than DisplayPort for the same monitors Regression timing: Problem correlates precisely with libddcutil4 → libddcutil5 upgrade Version evidence: libddcutil5 2.2.0-1 is a development version (2.2.0-dev) with apparent regressions Attempted Solutions The following configuration attempts had no effect on powerdevil startup time: Environment variables: POWERDEVIL_NO_DDC=1, DDCUTIL_SLEEP_MULTIPLIER=0.3 ddcutil configuration files: /etc/ddcutil/ddcutilrc with optimized parameters Systemd service overrides: Custom environment variables in service configuration Wrapper scripts: Custom powerdevil executable wrapper with environment settings Reproduction Steps Install Kubuntu 25.04 with libddcutil5 2.2.0-1 Connect multiple DisplayPort monitors (eventually older models from 2016-2017) Observe powerdevil startup time: time systemctl --user restart plasma-powerdevil.service Compare with HDMI connection on same monitors Significant user experience degradation during login (13+ second delays) No workaround available through configuration
I forgot to mention that all controls on the 2 screens works flawlessly and without lag, color temperature from the KDE Plasma settings, brightness from the taskbar widget, ... Everything is applied on the flight and i can see it in the OSD menus of the 2 screens.
I’ve been experiencing the same issue repeatedly in the past. However, after the latest system update (with ddcutil still at version 2.2.0-1), this problem no longer seems to reproduce on my Arch Linux laptop. Perhaps this issue is also related to other packages? Below is the package update log. [2025-07-27T14:36:29+0800] [ALPM] upgraded alsa-card-profiles (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded libpipewire (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded lib32-libpipewire (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded pipewire (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded lib32-pipewire (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded libdeflate (1.23-1 -> 1.24-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded libdovi (3.3.1-1 -> 3.3.2-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded libnvme (1.14-1 -> 1.15-1) [2025-07-27T14:36:29+0800] [ALPM] upgraded linux-cachyos (6.15.7-2 -> 6.15.8-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded linux-cachyos-headers (6.15.7-2 -> 6.15.8-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded luajit (2.1.1748459687-1 -> 2.1.1753364724-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded pipewire-audio (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded pipewire-session-manager (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded pipewire-jack (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded pipewire-pulse (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded pulse-native-provider (1:1.4.6-1 -> 1:1.4.7-1) [2025-07-27T14:36:30+0800] [ALPM] upgraded qt6-base (6.9.1-4 -> 6.9.1-5) [2025-07-27T14:36:31+0800] [ALPM] upgraded telegram-desktop (5.16.4-1 -> 5.16.6-1) [2025-07-25T20:25:50+0800] [ALPM] upgraded bash (5.3.0-1 -> 5.3.3-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded ca-certificates-mozilla (3.113.1-1 -> 3.114-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded fastfetch (2.48.0-1 -> 2.48.1-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded nspr (4.36-1 -> 4.37-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded nss (3.113.1-1 -> 3.114-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded pixman (0.46.2-1 -> 0.46.4-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded libopenmpt (0.8.1-1 -> 0.8.2-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded firefox (140.0.4-1 -> 141.0-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded firefox-i18n-zh-cn (140.0.4-1 -> 141.0-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded gettext (0.25.1-1 -> 0.26-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded hmcl (3.6.14-2 -> 3.6.15-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded less (1:668-1 -> 1:679-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded lib32-glibc (2.41+r48+g5cb575ca9a3d-1 -> 2.41+r65+ge7c419a29575-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded lib32-libx11 (1.8.12-1 -> 1.8.12-2) [2025-07-25T20:25:51+0800] [ALPM] upgraded lib32-llvm-libs (1:20.1.6-1 -> 1:20.1.8-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded lib32-nspr (4.36-1 -> 4.37-1) [2025-07-25T20:25:51+0800] [ALPM] upgraded lib32-nss (3.113.1-1 -> 3.114-1) [2025-07-25T20:25:52+0800] [ALPM] upgraded linux-cachyos (6.15.7-1 -> 6.15.7-2) [2025-07-25T20:25:53+0800] [ALPM] upgraded linux-cachyos-headers (6.15.7-1 -> 6.15.7-2) [2025-07-25T20:25:53+0800] [ALPM] upgraded nodejs (24.4.1-1 -> 24.4.1-2) [2025-07-25T20:25:53+0800] [ALPM] upgraded npm (11.4.2-1 -> 11.5.1-1) [2025-07-25T20:25:53+0800] [ALPM] upgraded opencv (4.12.0-1 -> 4.12.0-2) [2025-07-25T20:25:53+0800] [ALPM] upgraded phonon-qt6 (4.12.0-4 -> 4.12.0-5) [2025-07-25T20:25:53+0800] [ALPM] upgraded qt6-declarative (6.9.1-1 -> 6.9.1-2) [2025-07-25T20:25:54+0800] [ALPM] upgraded qt6-webengine (6.9.1-1 -> 6.9.1-2) [2025-07-25T20:25:54+0800] [ALPM] upgraded tevent (1:0.16.2-1 -> 1:0.17.0-1) [2025-07-25T20:25:54+0800] [ALPM] upgraded yt-dlp (2025.06.30-1 -> 2025.07.21-1) There is some information. Operating System: Arch Linux WM: KWin (Wayland) KDE Plasma Version: 6.4.3 KDE Frameworks Version: 6.16.0 Qt Version: 6.9.1 Kernel Version: 6.15.8-1-cachyos (64-bit) Graphics Platform: Wayland Processors: 12 × 12th Gen Intel® Core™ i5-12450H Graphics Processor: Intel® Graphics Display (CMN162B): 1920x1200 @ 60 Hz (as 1536x960) in 16" [Built-in] Manufacturer: LENOVO System Version: XiaoXin 16 IAH8 ddcutil version: 2.2.0-1 powerdevil version: 6.4.3-1
Here is my current report === SYSTEM INFO === No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 25.04 Release: 25.04 Codename: plucky KDE Plasma: 6.3.4 Qt: 5.15.15 Kernel: 6.14.0-24-generic === PACKAGE VERSIONS === ddcutil: 2.2.0-1 gstreamer1.0-pipewire:amd64: 1.2.7-1ubuntu5.1 kdeplasma-addons-data: 4:6.3.4-0ubuntu1 libddcutil5:amd64: 2.2.0-1 libegl-mesa0:amd64: 25.0.7-0ubuntu0.25.04.1 libegl-mesa0:i386: 25.0.7-0ubuntu0.25.04.1 libgl1-mesa-dri:amd64: 25.0.7-0ubuntu0.25.04.1 libgl1-mesa-dri:i386: 25.0.7-0ubuntu0.25.04.1 libglu1-mesa:amd64: 9.0.2-1.1build1 libglu1-mesa-dev:amd64: 9.0.2-1.1build1 libglx-mesa0:amd64: 25.0.7-0ubuntu0.25.04.1 libglx-mesa0:i386: 25.0.7-0ubuntu0.25.04.1 libkpipewire-data: 6.3.4-0ubuntu1 libkpipewire6:amd64: 6.3.4-0ubuntu1 libkpipewiredmabuf6:amd64: 6.3.4-0ubuntu1 libkpipewirerecord6:amd64: 6.3.4-0ubuntu1 libpipewire-0.3-0t64:amd64: 1.2.7-1ubuntu5.1 libpipewire-0.3-common: 1.2.7-1ubuntu5.1 libpipewire-0.3-modules:amd64: 1.2.7-1ubuntu5.1 libplasma-geolocation-interface6:amd64: 4:6.3.4-0ubuntu1 libplasma5support-data: 4:6.3.4-0ubuntu1 libplasma5support6:amd64: 4:6.3.4-0ubuntu1 libplasma6:amd64: 6.3.4-0ubuntu1 libplasmaactivities6:amd64: 6.3.4-0ubuntu1 libplasmaactivitiesstats1:amd64: 6.3.4-0ubuntu1 libplasmaquick6:amd64: 6.3.4-0ubuntu1 libpowerdevilcore2:amd64: 4:6.3.4-0ubuntu1 libreoffice-plasma: 4:25.2.4-0ubuntu0.25.04.1 mesa-libgallium:amd64: 25.0.7-0ubuntu0.25.04.1 mesa-libgallium:i386: 25.0.7-0ubuntu0.25.04.1 mesa-utils: 9.0.0-2 mesa-utils-bin:amd64: 9.0.0-2 mesa-va-drivers:amd64: 25.0.7-0ubuntu0.25.04.1 mesa-va-drivers:i386: 25.0.7-0ubuntu0.25.04.1 mesa-vdpau-drivers:amd64: 25.0.7-0ubuntu0.25.04.1 mesa-vdpau-drivers:i386: 25.0.7-0ubuntu0.25.04.1 mesa-vulkan-drivers:amd64: 25.0.7-0ubuntu0.25.04.1 mesa-vulkan-drivers:i386: 25.0.7-0ubuntu0.25.04.1 pipewire:amd64: 1.2.7-1ubuntu5.1 pipewire-bin: 1.2.7-1ubuntu5.1 pipewire-pulse: 1.2.7-1ubuntu5.1 plasma-activities-bin: 6.3.4-0ubuntu1 plasma-browser-integration: 6.3.4-0ubuntu1 plasma-calendar-addons:amd64: 4:6.3.4-0ubuntu1 plasma-dataengines-addons:amd64: 4:6.3.4-0ubuntu1 plasma-desktop: 4:6.3.4-0ubuntu1 plasma-desktop-data: 4:6.3.4-0ubuntu1 plasma-desktoptheme: 6.3.4-0ubuntu1 plasma-discover: 6.3.4-0ubuntu1 plasma-discover-backend-flatpak: 6.3.4-0ubuntu1 plasma-discover-backend-fwupd: 6.3.4-0ubuntu1 plasma-discover-backend-snap: 6.3.4-0ubuntu1 plasma-discover-common: 6.3.4-0ubuntu1 plasma-discover-notifier: 6.3.4-0ubuntu1 plasma-disks: 6.3.4-0ubuntu1 plasma-distro-release-notifier: 20241226-0ubuntu2 plasma-firewall: 6.3.4-0ubuntu1 plasma-integration: 6.3.4-0ubuntu1 plasma-nm: 4:6.3.4-0ubuntu1 plasma-pa: 4:6.3.4-0ubuntu1 plasma-systemmonitor: 6.3.4-0ubuntu1 plasma-theme-oxygen: 4:6.3.4-0ubuntu1 plasma-thunderbolt: 6.3.4-0ubuntu1 plasma-vault: 6.3.4-0ubuntu1 plasma-wallpapers-addons:amd64: 4:6.3.4-0ubuntu1 plasma-welcome: 6.3.4-0ubuntu1 plasma-widgets-addons: 4:6.3.4-0ubuntu1 plasma-workspace: 4:6.3.4-0ubuntu2 plasma-workspace-data: 4:6.3.4-0ubuntu2 plasma-workspace-wallpapers: 4:6.3.4-0ubuntu1 plasma5-integration: 6.3.4-0ubuntu1 powerdevil: 4:6.3.4-0ubuntu1 powerdevil-data: 4:6.3.4-0ubuntu1 qml6-module-org-kde-pipewire:amd64: 6.3.4-0ubuntu1 qml6-module-org-kde-plasma-plasma5support:amd64: 4:6.3.4-0ubuntu1 Could it be that dccutil 2.2.0-1 isn 't working well with my PowerDevil 6.3.4 version ?? I don't know.
Any news on this issue ?
Can you upgrade to Plasma 6.4.5 and ddcutil 2.2.1 and try again? There have been some fixed in those versions.
I need to look on how to deploy these version on my Kubuntu 25.04 as this doesn't seem to be delivered by the current update channel, i am still with Plasma 6.3.4 and ddcutil 2.2.0-dev.
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(In reply to Nate Graham from comment #5) > Can you upgrade to Plasma 6.4.5 and ddcutil 2.2.1 and try again? There have > been some fixed in those versions. Hi, i just upgraded to Kubuntu 25.10, i got Plasma 6.4.5 but still ddcutil 2.2.0-dev, at this stage, still the same behavior, the command takes around 12-13s : mauro@mauro-amd:~$ time ddcutil detect -v Display 1 I2C bus: /dev/i2c-9 DRM connector: card1-DP-1 /sys/class/drm/card1-DP-1/dpms On /sys/class/drm/card1-DP-1/enabled enabled /sys/class/drm/card1-DP-1/status connected /sys/class/drm/card1-DP-1/connector_id 94 Driver: amdgpu EDID exists: true I2C address 0x37 (DDC) responsive: true Is LVDS or EDP display: false Is laptop display by EDID: false Is laptop display: false /sys/bus/i2c/devices/i2c-9/name AMDGPU DM aux hw bus 0 PCI device path: /sys/devices/pci0000:00/0000:00:03.1/0000:0b:00.0/0000:0c:00.0/0000:0d:00.0/drm/card1/card1-DP-1/i2c-9 EDID synopsis: Mfg id: AUS - UNK Model: ROG PG278QR Product code: 10161 (0x27b1) Serial number: #ASPmg9zGzyzd Binary serial number: 63523 (0x0000f823) Manufacture year: 2016, Week: 43 EDID version: 1.4 Extra descriptor: Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8 Supported features: Digital display type: RGB 4:4:4 Standard sRGB color space: False White x,y: 0.312, 0.329 Red x,y: 0.640, 0.330 Green x,y: 0.300, 0.600 Blue x,y: 0.150, 0.060 Extension blocks: 1 EDID source: SYSFS EDID hex dump: +0 +4 +8 +c 0 4 8 c +0000 00 ff ff ff ff ff ff 00 06 b3 b1 27 23 f8 00 00 ...........'#... +0010 2b 1a 01 04 a5 3c 22 78 06 ee 91 a3 54 4c 99 26 +....<"x....TL.& +0020 0f 50 54 21 08 00 01 01 01 01 01 01 01 01 01 01 .PT!............ +0030 01 01 01 01 01 01 56 5e 00 a0 a0 a0 29 50 30 20 ......V^....)P0 +0040 35 00 56 50 21 00 00 1a 00 00 00 ff 00 23 41 53 5.VP!........#AS +0050 50 6d 67 39 7a 47 7a 79 7a 64 00 00 00 fd 00 1e Pmg9zGzyzd...... +0060 90 22 de 3b 01 0a 20 20 20 20 20 20 00 00 00 fc .".;.. .... +0070 00 52 4f 47 20 50 47 32 37 38 51 52 0a 20 01 4f .ROG PG278QR. .O VCP version: 2.2 Controller mfg: Not defined - a manufacturer designed controller Firmware version: 4.1 Monitor uses all data bytes 0 in DDC reply packet to indicate unsupported feature. Current dynamic sleep adjustment multiplier: 0.70 Monitor Model Id: AUS-ROG_PG278QR-10161 Feature definition file AUS-ROG_PG278QR-10161.mccs not found. Display 2 I2C bus: /dev/i2c-10 DRM connector: card1-DP-2 /sys/class/drm/card1-DP-2/dpms On /sys/class/drm/card1-DP-2/enabled enabled /sys/class/drm/card1-DP-2/status connected /sys/class/drm/card1-DP-2/connector_id 104 Driver: amdgpu EDID exists: true I2C address 0x37 (DDC) responsive: true Is LVDS or EDP display: false Is laptop display by EDID: false Is laptop display: false /sys/bus/i2c/devices/i2c-10/name AMDGPU DM aux hw bus 1 PCI device path: /sys/devices/pci0000:00/0000:00:03.1/0000:0b:00.0/0000:0c:00.0/0000:0d:00.0/drm/card1/card1-DP-2/i2c-10 EDID synopsis: Mfg id: ACI - Ancor Communications Inc Model: ROG PG279Q Product code: 10220 (0x27ec) Serial number: #ASONXagl2MLd Binary serial number: 10514 (0x00002912) Manufacture year: 2016, Week: 2 EDID version: 1.4 Extra descriptor: Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8 Supported features: Digital display type: RGB 4:4:4 Standard sRGB color space: False White x,y: 0.312, 0.329 Red x,y: 0.640, 0.330 Green x,y: 0.300, 0.600 Blue x,y: 0.150, 0.060 Extension blocks: 1 EDID source: SYSFS EDID hex dump: +0 +4 +8 +c 0 4 8 c +0000 00 ff ff ff ff ff ff 00 04 69 ec 27 12 29 00 00 .........i.'.).. +0010 02 1a 01 04 a5 3c 22 78 06 ee 91 a3 54 4c 99 26 .....<"x....TL.& +0020 0f 50 54 21 08 00 01 01 01 01 01 01 01 01 01 01 .PT!............ +0030 01 01 01 01 01 01 56 5e 00 a0 a0 a0 29 50 30 20 ......V^....)P0 +0040 35 00 56 50 21 00 00 1a 00 00 00 ff 00 23 41 53 5.VP!........#AS +0050 4f 4e 58 61 67 6c 32 4d 4c 64 00 00 00 fd 00 1e ONXagl2MLd...... +0060 90 22 de 3b 01 0a 20 20 20 20 20 20 00 00 00 fc .".;.. .... +0070 00 52 4f 47 20 50 47 32 37 39 51 0a 20 20 01 31 .ROG PG279Q. .1 VCP version: 2.2 Controller mfg: Not defined - a manufacturer designed controller Firmware version: 5.50 Monitor uses all data bytes 0 in DDC reply packet to indicate unsupported feature. Current dynamic sleep adjustment multiplier: 0.70 Monitor Model Id: ACI-ROG_PG279Q-10220 Feature definition file ACI-ROG_PG279Q-10220.mccs not found. real 0m12,491s user 0m0,011s sys 0m0,846s I need to try with 2.2.1 and will report.
TBH this is sounding like a bug in ddcutil itself.
Looks like, i finally got the time to update ddcutil to 2.2.1, and the end result is the same about the time to detect monitors. However, my session boots almost as fast as before now, for whatever reason, since i have Plasma 6.4.5. I did not pay attention to it, as the time to start powerdevil service is still as long as ddcutil but yet, my session gets started much faster than before, which is already something : mauro@mauro-amd:~$ time ddcutil detect -v Display 1 I2C bus: /dev/i2c-9 DRM_connector: card1-DP-1 /sys/class/drm/card1-DP-1/dpms On /sys/class/drm/card1-DP-1/enabled enabled /sys/class/drm/card1-DP-1/status connected /sys/class/drm/card1-DP-1/connector_id 94 Driver: amdgpu I2C address 0x30 (EDID block#) present: false EDID exists: true I2C address 0x37 (DDC) responsive: true Is LVDS or EDP display: false Is laptop display by EDID: false Is laptop display: false /sys/bus/i2c/devices/i2c-9/name AMDGPU DM aux hw bus 0 PCI device path: /sys/devices/pci0000:00/0000:00:03.1/0000:0b:00.0/0000:0c:00.0/0000:0d:00.0/drm/card1/card1-DP-1/i2c-9 EDID synopsis: Mfg id: AUS - UNK Model: ROG PG278QR Product code: 10161 (0x27b1) Serial number: #ASPmg9zGzyzd Binary serial number: 63523 (0x0000f823) Manufacture year: 2016, Week: 43 EDID version: 1.4 Extra descriptor: Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8 Supported features: Digital display type: RGB 4:4:4 Standard sRGB color space: False White x,y: 0.312, 0.329 Red x,y: 0.640, 0.330 Green x,y: 0.300, 0.600 Blue x,y: 0.150, 0.060 Extension blocks: 1 EDID source: SYSFS EDID hex dump: +0 +4 +8 +c 0 4 8 c +0000 00 ff ff ff ff ff ff 00 06 b3 b1 27 23 f8 00 00 ...........'#... +0010 2b 1a 01 04 a5 3c 22 78 06 ee 91 a3 54 4c 99 26 +....<"x....TL.& +0020 0f 50 54 21 08 00 01 01 01 01 01 01 01 01 01 01 .PT!............ +0030 01 01 01 01 01 01 56 5e 00 a0 a0 a0 29 50 30 20 ......V^....)P0 +0040 35 00 56 50 21 00 00 1a 00 00 00 ff 00 23 41 53 5.VP!........#AS +0050 50 6d 67 39 7a 47 7a 79 7a 64 00 00 00 fd 00 1e Pmg9zGzyzd...... +0060 90 22 de 3b 01 0a 20 20 20 20 20 20 00 00 00 fc .".;.. .... +0070 00 52 4f 47 20 50 47 32 37 38 51 52 0a 20 01 4f .ROG PG278QR. .O VCP version: 2.2 Controller mfg: Not defined - a manufacturer designed controller Firmware version: 4.1 Monitor uses all data bytes 0 in DDC reply packet to indicate unsupported feature. Current dynamic sleep adjustment multiplier: 0.70 Monitor Model Id: AUS-ROG_PG278QR-10161 Feature definition file AUS-ROG_PG278QR-10161.mccs not found. Display 2 I2C bus: /dev/i2c-10 DRM_connector: card1-DP-2 /sys/class/drm/card1-DP-2/dpms On /sys/class/drm/card1-DP-2/enabled enabled /sys/class/drm/card1-DP-2/status connected /sys/class/drm/card1-DP-2/connector_id 104 Driver: amdgpu I2C address 0x30 (EDID block#) present: false EDID exists: true I2C address 0x37 (DDC) responsive: true Is LVDS or EDP display: false Is laptop display by EDID: false Is laptop display: false /sys/bus/i2c/devices/i2c-10/name AMDGPU DM aux hw bus 1 PCI device path: /sys/devices/pci0000:00/0000:00:03.1/0000:0b:00.0/0000:0c:00.0/0000:0d:00.0/drm/card1/card1-DP-2/i2c-10 EDID synopsis: Mfg id: ACI - Ancor Communications Inc Model: ROG PG279Q Product code: 10220 (0x27ec) Serial number: #ASONXagl2MLd Binary serial number: 10514 (0x00002912) Manufacture year: 2016, Week: 2 EDID version: 1.4 Extra descriptor: Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8 Supported features: Digital display type: RGB 4:4:4 Standard sRGB color space: False White x,y: 0.312, 0.329 Red x,y: 0.640, 0.330 Green x,y: 0.300, 0.600 Blue x,y: 0.150, 0.060 Extension blocks: 1 EDID source: SYSFS EDID hex dump: +0 +4 +8 +c 0 4 8 c +0000 00 ff ff ff ff ff ff 00 04 69 ec 27 12 29 00 00 .........i.'.).. +0010 02 1a 01 04 a5 3c 22 78 06 ee 91 a3 54 4c 99 26 .....<"x....TL.& +0020 0f 50 54 21 08 00 01 01 01 01 01 01 01 01 01 01 .PT!............ +0030 01 01 01 01 01 01 56 5e 00 a0 a0 a0 29 50 30 20 ......V^....)P0 +0040 35 00 56 50 21 00 00 1a 00 00 00 ff 00 23 41 53 5.VP!........#AS +0050 4f 4e 58 61 67 6c 32 4d 4c 64 00 00 00 fd 00 1e ONXagl2MLd...... +0060 90 22 de 3b 01 0a 20 20 20 20 20 20 00 00 00 fc .".;.. .... +0070 00 52 4f 47 20 50 47 32 37 39 51 0a 20 20 01 31 .ROG PG279Q. .1 VCP version: 2.2 Controller mfg: Not defined - a manufacturer designed controller Firmware version: 5.50 Monitor uses all data bytes 0 in DDC reply packet to indicate unsupported feature. Current dynamic sleep adjustment multiplier: 0.70 Monitor Model Id: ACI-ROG_PG279Q-10220 Feature definition file ACI-ROG_PG279Q-10220.mccs not found. real 0m12,399s user 0m0,007s sys 0m0,849s mauro@mauro-amd:~$ ddcutil --version ddcutil 2.2.1 Copyright (C) 2015-2025 Sanford Rockowitz License GPLv2: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. mauro@mauro-amd:~$
*** Bug 509759 has been marked as a duplicate of this bug. ***