Bug 494877

Summary:	Brightness Controls only operative as software instead of DDC/CI for Dell Monitor
Product:	[Plasma] plasmashell	Reporter:	Ben <globalunity>
Component:	Power management & brightness	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED DOWNSTREAM
Severity:	normal	CC:	globalunity, natalie_clarius, nate
Priority:	NOR
Version First Reported In:	6.2.4
Target Milestone:	1.0
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Ben 2024-10-16 17:31:52 UTC

SUMMARY

All three monitors effected by Brightness as Software Only - no DDC/CI Control for Dell Monitor


MAKE: Dell
MODEL: P2412H

Connection:
 - PC: Motherboard HDMI Port > HDMI-to-DVI Cable > Monitor DVI Port
 - Intel HD GPU

Monitor is connected to Motherboard GPU - GPU Specifications:

GPU Name
Intel® UHD Graphics 750

I also have an AMD Radeon RX 6600 PCI-E Video Card



STEPS TO REPRODUCE:

1.  Change Brightness slider control for Dell Monitor via mouse of wheel or mouse button drag



OBSERVED RESULT:

Dell Monitor Brightness changes only as software - not through DDC/CI



EXPECTED RESULT:

Dell Monitor Brightness changes through DDC/CI - Presumably with Dell monitor on-screen brightness display imagery


SOFTWARE/OS VERSIONS:

Operating System: openSUSE Tumbleweed 20241014
KDE Plasma Version: 6.2.0
KDE Frameworks Version: 6.7.0
Qt Version: 6.7.3
Kernel Version: 6.11.2-1-default (64-bit)
Graphics Platform: Wayland
Processors: 12 × 11th Gen Intel® Core™ i5-11500 @ 2.70GHz
Memory: 31.2 GiB of RAM
Graphics Processor: AMD Radeon RX 6600
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: H510M DS2V





ADDITIONAL INFORMATION

Comment 1 Ben 2024-10-16 17:50:31 UTC

Monitor has no HDMI Port
Monitor has 1 VGA Port
Monitor has 1 DVI Port

Comment 2 Nate Graham 2025-05-16 15:19:08 UTC

Thanks for the bug report, and sorry we weren't able to look into this yet. Can I ask you to see if the problem still happens at all in Plasma 6.3.5 or later and ddcutil 2.2.0 or later? Thanks a lot!

If so, I suspect something getting lost in the HDMI-to-DVI translation, and it's a hardware issue.

Comment 3 Ben 2025-05-17 02:38:07 UTC

Im currently on KDE INFO:

Operating System: openSUSE Tumbleweed 20250514
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.0
Kernel Version: 6.14.6-1-default (64-bit)
Graphics Platform: Wayland
Processors: 12 × 11th Gen Intel® Core™ i5-11500 @ 2.70GHz
Memory: 31.2 GiB of RAM
Graphics Processor: AMD Radeon RX 6600
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: H510M DS2V


I reviewed the DELL P2412H Monitor DDC/CI Information in this PDF about it:

https://dl.dell.com/manuals/all-products/esuprt_display_projector/esuprt_display/dell-p2412h_user's%20guide_en-us.pdf

The manual does not actually show or demonstrate any monitor "on-screen' displays showing that any DDC/CI signals or commands
are taking place to control the display at all

I did turn the DDC/CI control option OFF from the monitors own on-screen menu and varied the brightness from plasma
I could not see any discernable/visually noticeable differance with the monitor brightness changing with the DDC/CI Option turned on or off in the monitors menu

Despite this, I can accept that this is probably a hard-ware issue to do with the HDMI-to-DVI Converter