SUMMARY Every now and then, KDE Plasma decideds to dim my external monitor brightness to 30% even if I'm in the middle of typing--which would normally be no big deal except ... ddcutil cannot detect my external HDMI monitor connected to my Thunderbolt Dock. Consequently, the only way for me to undo the dimming is to use the controls on the monitor itself. KDE is somehow sending a DDC command to set my external dock HDMI monitor brightness in spite of the fact that ddcutil can't actually detect it. STEPS TO REPRODUCE 1. Work for a while 2. Monitor will dim to 30% 3. Monitor can't be reset except with physical monitor controls OBSERVED RESULT 30% brightness setting not adjustable from KDE EXPECTED RESULT Preferably, no dimming, but at least the ability to reset brightness without using physical monitor controls. SOFTWARE/OS VERSIONS Operating System: Fedora Linux 42 KDE Plasma Version: 6.4.5 KDE Frameworks Version: 6.18.0 Qt Version: 6.9.2 Kernel Version: 6.16.10-200.fc42.x86_64 (64-bit) Graphics Platform: Wayland Processors: 12 × 13th Gen Intel® Core™ i7-1355U Memory: 32 GiB of RAM (31.0 GiB usable) Graphics Processor: Intel® Iris® Xe Graphics Hardware: Processors: 12 × 13th Gen Intel® Core™ i7-1355U Memory: 32 GiB of RAM (31.0 GiB usable) Graphics Processor: Intel® Iris® Xe Graphics Manufacturer: LENOVO Product Name: 21HMCTO1WW System Version: ThinkPad X1 Carbon Gen 11 Lenovo Universal Thunderbolt 4 Dock ADDITIONAL INFORMATION ```% ddcutil --version ddcutil 2.2.1``` ```% ddcutil detect Invalid display I2C bus: /dev/i2c-10 DRM_connector: card1-eDP-1 EDID synopsis: Mfg id: SDC - UNK Model: Product code: 16787 (0x4193) Serial number: Binary serial number: 0 (0x00000000) Manufacture year: 2020, Week: 35 This is a laptop display. Laptop displays do not support DDC/CI.``` EDID: # card1-DP-6 ####################### Block 0, Base EDID: EDID Structure Version & Revision: 1.3 Vendor & Product Identification: Manufacturer: GSM Model: 30543 Serial Number: 496572 (0x000793bc) Made in: week 8 of 2020 Basic Display Parameters & Features: Digital display Maximum image size: 70 cm x 40 cm Gamma: 2.20 DPMS levels: Standby Suspend Off RGB color display First detailed timing is the preferred timing Color Characteristics: Red : 0.6806, 0.3115 Green: 0.2675, 0.6630 Blue : 0.1503, 0.0488 White: 0.3125, 0.3291 Established Timings I & II: DMT 0x04: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz DMT 0x09: 800x600 60.316541 Hz 4:3 37.879 kHz 40.000000 MHz DMT 0x10: 1024x768 60.003840 Hz 4:3 48.363 kHz 65.000000 MHz Standard Timings: DMT 0x52: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz DMT 0x10: 1024x768 60.003840 Hz 4:3 48.363 kHz 65.000000 MHz DMT 0x09: 800x600 60.316541 Hz 4:3 37.879 kHz 40.000000 MHz Detailed Timing Descriptors: DTD 1: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz (697 mm x 392 mm) Hfront 176 Hsync 88 Hback 296 Hpol P Vfront 8 Vsync 10 Vback 72 Vpol P Display Range Limits: Monitor ranges (GTF): 40-60 Hz V, 30-135 kHz H, max dotclock 600 MHz Display Product Name: 'LG HDR 4K' Display Product Serial Number: '008NTJJEL572' Extension blocks: 1 Checksum: 0x08 ---------------- Block 1, CTA-861 Extension Block: Revision: 3 Basic audio support Supports YCbCr 4:4:4 Supports YCbCr 4:2:2 Native detailed modes: 2 Audio Data Block: Linear PCM: Max channels: 2 Supported sample rates (kHz): 48 44.1 32 Supported sample sizes (bits): 24 20 16 Speaker Allocation Data Block: FL/FR - Front Left/Right Video Data Block: VIC 1: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz VIC 3: 720x480 59.940060 Hz 16:9 31.469 kHz 27.000000 MHz VIC 4: 1280x720 60.000000 Hz 16:9 45.000 kHz 74.250000 MHz VIC 16: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz VIC 18: 720x576 50.000000 Hz 16:9 31.250 kHz 27.000000 MHz VIC 31: 1920x1080 50.000000 Hz 16:9 56.250 kHz 148.500000 MHz VIC 32: 1920x1080 24.000000 Hz 16:9 27.000 kHz 74.250000 MHz VIC 34: 1920x1080 30.000000 Hz 16:9 33.750 kHz 74.250000 MHz VIC 97: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz VIC 96: 3840x2160 50.000000 Hz 16:9 112.500 kHz 594.000000 MHz VIC 95: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz VIC 94: 3840x2160 25.000000 Hz 16:9 56.250 kHz 297.000000 MHz VIC 93: 3840x2160 24.000000 Hz 16:9 54.000 kHz 297.000000 MHz YCbCr 4:2:0 Capability Map Data Block: VIC 97: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz VIC 96: 3840x2160 50.000000 Hz 16:9 112.500 kHz 594.000000 MHz Video Capability Data Block: YCbCr quantization: No Data RGB quantization: Selectable (via AVI Q) PT scan behavior: Always Underscanned IT scan behavior: Always Underscanned CE scan behavior: Always Underscanned Colorimetry Data Block: BT2020YCC BT2020RGB HDR Static Metadata Data Block: Electro optical transfer functions: Traditional gamma - SDR luminance range SMPTE ST2084 Supported static metadata descriptors: Static metadata type 1 Desired content max luminance: 89 (343.724 cd/m^2) Desired content max frame-average luminance: 89 (343.724 cd/m^2) Desired content min luminance: 82 (0.355 cd/m^2) Detailed Timing Descriptors: DTD 2: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz (697 mm x 392 mm) Hfront 176 Hsync 88 Hback 296 Hpol P Vfront 8 Vsync 10 Vback 72 Vpol P DTD 3: 2560x1440 59.950550 Hz 16:9 88.787 kHz 241.500000 MHz (697 mm x 392 mm) Hfront 48 Hsync 32 Hback 80 Hpol P Vfront 3 Vsync 5 Vback 33 Vpol N DTD 4: 1920x1080 59.933878 Hz 16:9 66.587 kHz 138.500000 MHz (697 mm x 392 mm) Hfront 42 Hsync 38 Hback 80 Hpol P Vfront 3 Vsync 5 Vback 23 Vpol N Checksum: 0x19 ---------------- Failures: Block 1, CTA-861 Extension Block: Video Capability Data Block: IT video formats are always underscanned, but bit 7 of Byte 3 of the CTA-861 Extension header is set to overscanned. EDID conformity: FAIL # card1-eDP-1 ####################### Block 0, Base EDID: EDID Structure Version & Revision: 1.4 Vendor & Product Identification: Manufacturer: SDC Model: 16787 Made in: week 35 of 2020 Basic Display Parameters & Features: Digital display Bits per primary color channel: 10 DisplayPort interface Maximum image size: 30 cm x 19 cm Gamma: 2.20 Supported color formats: RGB 4:4:4 First detailed timing includes the native pixel format and preferred refresh rate Color Characteristics: Red : 0.6796, 0.3203 Green: 0.2373, 0.7226 Blue : 0.1396, 0.0498 White: 0.3125, 0.3291 Established Timings I & II: none Standard Timings: none Detailed Timing Descriptors: DTD 1: 2880x1800 90.001438 Hz 16:10 169.203 kHz 500.840000 MHz (302 mm x 189 mm) Hfront 8 Hsync 32 Hback 40 Hpol P Vfront 8 Vsync 8 Vback 64 Vpol N DTD 2: 2880x1800 60.000958 Hz 16:10 169.203 kHz 500.840000 MHz (302 mm x 189 mm) Hfront 8 Hsync 32 Hback 40 Hpol P Vfront 8 Vsync 8 Vback 1004 Vpol N Alphanumeric Data String: 'ATNA40YK15-0 ' Extension blocks: 1 Checksum: 0x62 ---------------- Block 1, CTA-861 Extension Block: Revision: 3 Native detailed modes: 0 Colorimetry Data Block: BT2020RGB HDR Static Metadata Data Block: Electro optical transfer functions: Traditional gamma - SDR luminance range SMPTE ST2084 Supported static metadata descriptors: Static metadata type 1 Desired content max luminance: 116 (616.884 cd/m^2) Desired content max frame-average luminance: 96 (400.000 cd/m^2) Desired content min luminance: 7 (0.005 cd/m^2) Checksum: 0xb7 ---------------- EDID conformity: PASS
The symptoms sound similar to bug 508982. It's possible that the brightness is changing by itself because of a crash in powerdevil. Can you please run this and see if there are coredumps for powerdevil? sudo coredumpctl --reverse Thanks.
(In reply to TraceyC from comment #1) > The symptoms sound similar to bug 508982. It's possible that the brightness > is changing by itself because of a crash in powerdevil. Can you please run > this and see if there are coredumps for powerdevil? > > sudo coredumpctl --reverse > > Thanks. I don't see any crashes from powerdevil.
(In reply to disp1_kde from comment #2) > (In reply to TraceyC from comment #1) > > The symptoms sound similar to bug 508982. It's possible that the brightness > > is changing by itself because of a crash in powerdevil. Can you please run > > this and see if there are coredumps for powerdevil? > > > > sudo coredumpctl --reverse > > > > Thanks. > > I don't see any crashes from powerdevil. I will try to see if I can catch it today with ```journalctl --since "today" | grep -i power``` as well.
I still don't see a crash but journalctl has some odd stuff: ``` Oct 16 04:40:27 fedora kded6[1940]: kf.notifications: Failed to notify "Created too many similar notifications in quick succession" Oct 16 04:40:27 fedora kscreenlocker_greet[233136]: qml: The backend got an unknown wallpaper provider type. The wallpaper will now fall back to the default. Please check your wallp aper configuration! Oct 16 04:40:29 fedora kscreenlocker_greet[233136]: qt.qpa.wayland: Could not create EGL surface (EGL error 0x3000) Oct 16 04:40:29 fedora kscreenlocker_greet[233136]: qt.qpa.wayland: Could not create EGL surface (EGL error 0x3000) Oct 16 04:40:29 fedora kscreenlocker_greet[233136]: Failed to write to the pipe: Bad file descriptor. Oct 16 04:40:53 fedora systemd[1]: fprintd.service: Deactivated successfully. Oct 16 04:40:53 fedora audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=fprintd comm="systemd" exe="/usr/lib/systemd/syst emd" hostname=? addr=? terminal=? res=success' Oct 16 04:40:53 fedora audit: BPF prog-id=380 op=UNLOAD ```
🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME. For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging. Thank you for helping us make KDE software even better for everyone!
(In reply to TraceyC from comment #1) > The symptoms sound similar to bug 508982. It's possible that the brightness > is changing by itself because of a crash in powerdevil. Can you please run > this and see if there are coredumps for powerdevil? > > sudo coredumpctl --reverse > > Thanks. I said I had no crashes from powerdevil.
Created attachment 186354 [details] coredumpctl output
Cannot delete attachment. Please delete and I will reupload a different one.
Thanks for the clarification. I don't have the ability to delete the existing attachment either. If you create a new attachment, you can use "Obsoletes" and tick the checkmark next to the existing attachment.
Setting to NEEDSINFO since we're waiting on new logs