Bug 499269

Summary: On X11, Plasmashell, menues and QT tooltips don't composite with depth = 30
Product: [Plasma] kwin Reporter: Guido <guido.iodice>
Component: colour-managementAssignee: Marco Martin <notmart>
Status: RESOLVED UPSTREAM    
Severity: normal CC: guido.iodice, kde, nate, xaver.hugl
Priority: NOR    
Version First Reported In: 6.2.4   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Guido 2025-01-29 10:41:01 UTC 
Although the bug affects not only plasmashell I post it here for lack of better

SUMMARY
On X11, Plasmashell, menues and QT tooltips don't composite with depth = 30

STEPS TO REPRODUCE
1. Set 30 bpp per channel in Xorg.conf
2. Restart X


OBSERVED RESULT
Plasmashell, QT menues and QT tooltips have not shadows, rounded corners and transparency. 
Strangely, however, qtquick menus seem to have them in Systemsettings.
All the rest seems ok.


SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux 
KDE Plasma Version: 6.2.5
KDE Frameworks Version: 6.10.0
Qt Version: 6.8.1
Kernel Version: 6.13.0-1-MANJARO (64-bit)
Graphics Platform: X11
Processors: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
Memory: 15.4 GiB of RAM
Graphics Processor: Mesa Intel® Iris® Xe Graphics
Manufacturer: Dell Inc.
Product Name: Inspiron 5502

ADDITIONAL INFORMATION
Settings vulkan for qtquick doesn't solve the problem.
Comment 1 Nate Graham 2025-01-29 19:06:59 UTC 
On X11 it's the X server responsible for this I believe, but moving to KWin so the experts there can handle it.
Comment 2 Guido 2025-02-17 14:37:54 UTC 
(In reply to Nate Graham from comment #1)
> On X11 it's the X server responsible for this I believe, but moving to KWin
> so the experts there can handle it.

mmm... not sure, everything else is rendered correctly, with its shadows.
Comment 3 Zamundaaa 2025-02-17 21:47:37 UTC 
Yeah, this is almost certainly a client side bug. I don't know X11 stuff well enough to judge if it's in the graphics driver or in Qt, but if it works with other apps, it's most likely in Qt.

Note though that in general X11 with 30bpp is a basically unused and pretty much unsupported configuration. If you want to have apps use higher bit depths, you'll really want to switch to the Wayland session, where this works out of the box without such bugs.
Comment 4 Guido 2025-02-17 22:16:30 UTC 
(In reply to Zamundaaa from comment #3)
> Yeah, this is almost certainly a client side bug. I don't know X11 stuff
> well enough to judge if it's in the graphics driver or in Qt, but if it
> works with other apps, it's most likely in Qt.
> 
> Note though that in general X11 with 30bpp is a basically unused and pretty
> much unsupported configuration. If you want to have apps use higher bit
> depths, you'll really want to switch to the Wayland session, where this
> works out of the box without such bugs.

I don't like this continuous sponsorship of the move to Wayland.
If a user continues to use X11, you should understand that he has his reasons, which are certainly much more important than 30-bit colour.