Bug 487433 - KDE brightness control actually changes display's black level, not its brightness
Summary: KDE brightness control actually changes display's black level, not its bright...
Status: RESOLVED WORKSFORME
Alias: None
Product: Powerdevil
Classification: Unmaintained
Component: general (other bugs)
Version First Reported In: 6.0.4
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-05-23 15:53 UTC by Apicultor
Modified: 2024-07-16 03:46 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description Apicultor 2024-05-23 15:53:59 UTC
SUMMARY
KDE's brightness control is actually changing the black level of my displays (Fujitsu B24T-7).

STEPS TO REPRODUCE
1. Hover mouse pointer over brightness widget
2. Scroll mouse wheel
3. ???
4. Profit!

OBSERVED RESULT
Image is affected in a way that's hard to describe, like fading mostly to black, but at the same brightness.

EXPECTED RESULT
Backlight dims without affecting anything else.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.2.0
Qt Version: 6.7.0
Kernel Version: 6.6.31-1-lts (64-bit)
Graphics Platform: Wayland
Processors: 24 × Intel® Xeon® CPU E5-2690 v3 @ 2.60GHz
Memory: 125.7 GiB of RAM
Graphics Processor: NV117
Manufacturer: FUJITSU
Product Name: CELSIUS M740

ADDITIONAL INFORMATION
Output from `ddcui`:
---
Display number:  1
   I2C bus:              /dev/i2c-0
   Mfg Id:               FUS
   Model:                B24T-7 LED PG
   Product code:         2093
   Serial number:        YV6K040698
   Binary serial number: 40698 (0x00009efa)
   EDID:
              +0          +4          +8          +c            0   4   8   c   
      +0000   00 ff ff ff ff ff ff 00 1a b3 2d 08 fa 9e 00 00   ..........-.....
      +0010   10 18 01 03 80 35 1e 78 2a 0e c5 a5 55 50 9e 26   .....5.x*...UP.&
      +0020   12 50 54 a5 4b 00 81 c0 81 80 95 00 b3 00 d1 c0   .PT.K...........
      +0030   01 01 01 01 01 01 02 3a 80 18 71 38 2d 40 58 2c   .......:..q8-@X,
      +0040   45 00 13 2b 21 00 00 1e 00 00 00 fd 00 38 4c 1e   E..+!........8L.
      +0050   52 11 00 0a 20 20 20 20 20 20 00 00 00 fc 00 42   R...      .....B
      +0060   32 34 54 2d 37 20 4c 45 44 20 50 47 00 00 00 ff   24T-7 LED PG....
      +0070   00 59 56 36 4b 30 34 30 36 39 38 0a 20 20 01 6a   .YV6K040698.  .j
   VCP Version:          2.2
---
Display number:  2
   I2C bus:              /dev/i2c-4
   Mfg Id:               FUS
   Model:                B24T-7 LED PG
   Product code:         2093
   Serial number:        YV6K213876
   Binary serial number: 213876 (0x00034374)
   EDID:
              +0          +4          +8          +c            0   4   8   c   
      +0000   00 ff ff ff ff ff ff 00 1a b3 2d 08 74 43 03 00   ..........-.tC..
      +0010   30 19 01 03 80 35 1e 78 2a 0e c5 a5 55 50 9e 26   0....5.x*...UP.&
      +0020   12 50 54 a5 4b 00 81 c0 81 80 95 00 b3 00 d1 c0   .PT.K...........
      +0030   01 01 01 01 01 01 02 3a 80 18 71 38 2d 40 58 2c   .......:..q8-@X,
      +0040   45 00 13 2b 21 00 00 1e 00 00 00 fd 00 38 4c 1e   E..+!........8L.
      +0050   52 11 00 0a 20 20 20 20 20 20 00 00 00 fc 00 42   R...      .....B
      +0060   32 34 54 2d 37 20 4c 45 44 20 50 47 00 00 00 ff   24T-7 LED PG....
      +0070   00 59 56 36 4b 32 31 33 38 37 36 0a 20 20 01 27   .YV6K213876.  .'
   VCP Version:          2.2
---
Comment 1 Nate Graham 2024-05-23 20:20:49 UTC
This sounds very strange. Possibly a monitor firmware issue or something.

Could you maybe attach a phone video that shows the issue happening?
Comment 2 Bug Janitor Service 2024-06-07 03:46:13 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 3 mirh 2024-06-16 12:31:21 UTC
Something like this was also reported here.
https://github.com/xanderfrangos/twinkle-tray/issues/213
https://github.com/blackholeearth/Win10_BrightnessSlider/issues/60 

Supposedly, at least Siemens and Fujitsu use 0x13 (backlight control) rather than 0x10 (brightness).
Comment 4 Bug Janitor Service 2024-07-01 03:47:13 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 5 Bug Janitor Service 2024-07-16 03:46:36 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!