Bug 454186 - Kwin is not scaling 1080p resolution on a 4k screen correctly
Summary: Kwin is not scaling 1080p resolution on a 4k screen correctly
Status: RESOLVED DUPLICATE of bug 453696
Alias: None
Product: kwin
Classification: Plasma
Component: platform-x11-standalone (show other bugs)
Version: 5.24.90
Platform: Arch Linux Linux
: NOR major
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2022-05-21 21:13 UTC by Siddhartha
Modified: 2022-05-24 09:34 UTC (History)
2 users (show)

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


Attachments
kwin incorrect scaling (1.30 MB, image/jpeg)
2022-05-21 21:15 UTC, Siddhartha
Details

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Description Siddhartha 2022-05-21 21:13:28 UTC
I've a 1920x1080 resolution set on a 4K laptop screen. In Kwin master (773384b59f), Plasma is being rendered in only 1/4th of the laptop screen, as you can see in the attached photo. Downgrading to commit a23d23593b (from April) fixes the rendering to the full screen as expected.

I have not been able to do a git bisect between these two commits yet to figure out the first bad commit. If a fix is not immediately obvious, let me know and I'll try to perform the git bisect sometime later.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.25.80
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.4
Kernel Version: 5.17.9-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 8 × 11th Gen Intel® Core™ i7-1165G7 @ 2.80GHz
Graphics Processor: Mesa Intel® Xe Graphics
Comment 1 Siddhartha 2022-05-21 21:15:06 UTC
Created attachment 149097 [details]
kwin incorrect scaling
Comment 2 Nate Graham 2022-05-23 18:56:27 UTC
A more precise bisect would be lovely, if you can manage it.
Comment 3 Siddhartha 2022-05-23 20:11:41 UTC
So the first bad commit is a4a2ee042 Refactor output mode abstractions.
It's parent commit 6b4daeddc9 works okay for me.
Comment 4 Siddhartha 2022-05-23 20:22:11 UTC
Here is my xrandr output. In master, setting resolution to "3840x2160" works but not for "1920x1080".

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
   3840x2160     60.00 +  59.97  
   3200x1800     59.96    59.94  
   2880x1620     59.96    59.97  
   2560x1600     59.99    59.97  
   2560x1440     59.99    59.96    59.95  
   2048x1536     60.00  
   1920x1440     60.00  
   1856x1392     60.01  
   1792x1344     60.01  
   2048x1152     59.99    59.98    59.90    59.91  
   1920x1200     59.88    59.95  
   1920x1080     60.01*   59.97    59.96    59.93  
   1600x1200     60.00  
   1680x1050     59.95    59.88  
   1400x1050     59.98  
   1600x900      59.99    59.94    59.95    59.82  
   1280x1024     60.02  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1440x810      60.00    59.97  
   1368x768      59.88    59.85  
   1280x800      59.99    59.97    59.81    59.91  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   700x450       59.96    59.88  
   640x480       60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   640x400       59.88    59.98  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
Comment 5 Zamundaaa 2022-05-24 09:34:10 UTC
*** This bug has been marked as a duplicate of bug 453696 ***