Bug 460300 - 100% global scale is completely wrong
Summary: 100% global scale is completely wrong
Status: RESOLVED WORKSFORME
Alias: None
Product: KScreen
Classification: Plasma
Component: common (other bugs)
Version First Reported In: 5.25.5
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: kscreen-bugs-null@kde.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-10-12 12:15 UTC by avalonvales
Modified: 2023-05-20 03:45 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 5.26.1
Sentry Crash Report:


Attachments
Images (3.36 MB, application/gzip)
2022-10-12 12:15 UTC, avalonvales
Details

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Description avalonvales 2022-10-12 12:15:57 UTC
Created attachment 152743 [details]
Images

SUMMARY

Setting display to 100% global scale is resulting in a terrible experience. I had global scale set to 100% prior to encountering this bug so I'm confident this is not what it is supposed to look like at 1080p.

Potentially useful info, not sure if necessary to reproduce: I've a 1080p laptop monitor, I've always used external 1080p monitors without hassle. This time I connected my laptop to a 4K TV. I quickly realized the default scaling (100%) looks terrible at 4K, so I opened display configuration, tried to set it to 200% or 300%, and clicked "apply". It then showed the popup saying changes would only take effect after a reboot, so I reverted it back to 100%, applied settings, and disconnected the display because I was just testing. Since rebooting, I haven't connected my laptop to the TV anymore, but as you can see, 100% scale is just blatantly wrong. 

I've rebooted several times since, having set the global scale back to 100% on the GUI, but the issue persists, making it borderline unusable. Thankfully, values higher than 100% still scale as expected, so I've been using 106.25% which is the closest I can get to what I'm used to.


OBSERVED RESULT
100% global scale looks absurdly large at 1080p (see attachment).

EXPECTED RESULT
100% global scale looks similar to 106.25% at 1080p (see attachment).

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.25.5
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.6
Kernel Version: 5.19.13-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 12 × Intel® Core™ i7-9750H CPU @ 2.60GHz
Memory: 15.5 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1660 Ti/PCIe/SSE2
Manufacturer: LENOVO
Product Name: 81Q6
System Version: Legion Y545

ADDITIONAL INFORMATION
Comment 1 Nate Graham 2022-10-12 19:19:37 UTC
Do you happen to have the PLASMA_USE_QT_SCALING=1 environment variable set?
Comment 2 avalonvales 2022-10-12 20:59:14 UTC
(In reply to Nate Graham from comment #1)
> Do you happen to have the PLASMA_USE_QT_SCALING=1 environment variable set?

Hi Nate. echo $PLASMA_USE_QT_SCALING suggests that variable is unset.

Is there anything else you would like me to check?
Comment 3 Nate Graham 2022-10-14 17:43:57 UTC
You're hitting an issue whereby the scale slider inappropriately says it's showing 100% scale when it really isn't. This was just fixed today by https://invent.kde.org/plasma/kscreen/-/commit/d3e2f09626e56a04a6c1fd01b033d63daf9c5fe3 for Plasma 5.26.1

In general, the mixed-DPI use case is quite bad on X11 and I would recommend trying Wayland instead.
Comment 4 avalonvales 2022-10-14 22:29:05 UTC
(In reply to Nate Graham from comment #3)
> You're hitting an issue whereby the scale slider inappropriately says it's
> showing 100% scale when it really isn't. 

Hi, thank you. I suspected as much.

Does that mean that when my system updates this should fix itself automatically? This is unfortunately still bumming me out -_-...
Comment 5 Nate Graham 2022-10-14 22:29:58 UTC
Yep, it should be fixed with Plasma 5.26.1.
Comment 6 avalonvales 2022-10-14 22:33:20 UTC
(In reply to Nate Graham from comment #5)
> Yep, it should be fixed with Plasma 5.26.1.

Cool, thank you!
Comment 7 avalonvales 2023-04-19 02:42:42 UTC
(In reply to Nate Graham from comment #5)
> Yep, it should be fixed with Plasma 5.26.1.

I'm still experiencing this bug as of 5.27.4.

https://youtu.be/3qYtrb748u8

For context, issue remains even after reboot. Started happening specifically after I disconnected my laptop from my external monitor, as with the last time I had this problem. Both monitors are 1080p.
 
While I wait for a fix, could you tell me which file I need to edit to actually change the scale.
Comment 8 Nate Graham 2023-04-19 16:03:39 UTC
After changing the global scale to 100%, please paste the output of `grep -A 5 "KScreen" ~/.config/kdeglobals` in a terminal window.
Comment 9 avalonvales 2023-04-19 17:19:10 UTC
(In reply to Nate Graham from comment #8)
> After changing the global scale to 100%, please paste the output of `grep -A
> 5 "KScreen" ~/.config/kdeglobals` in a terminal window.

Changed scale to 100% in the Display Configuration menu, clicked "Apply", rebooted. Output of command:

```
[KScreen]
ScreenScaleFactors=DP-0=1;DP-1=1;HDMI-0=1;DP-2=1;DP-3=1;DP-4=1;

[PreviewSettings]
MaximumRemoteSize=0
```

Display corrects value for larger values (I've been using 106.25% as a compromise).
Comment 10 avalonvales 2023-04-19 17:33:02 UTC
Can't edit typo in the last comment, but I meant that the "ScaleFactor" value isn't missing:

[KScreen]
ScaleFactor=1.0625
ScreenScaleFactors=DP-0=1.0625;DP-1=1.0625;HDMI-0=1.0625;DP-2=1.0625;DP-3=1.0625;DP-4=1.0625;

[PreviewSettings]
MaximumRemoteSize=0
Comment 11 Nate Graham 2023-04-20 15:16:46 UTC
Ok, can you run some test some things for me?

1. In your ~/.config/kdeglobals file, replace "ScaleFactor=1.0625" with "ScaleFactor=1", then do the same for the "ScreenScaleFactors" line, and then reboot. Is everything better now?

2. Click the "Defaults" button on the Display & Monitor page in System Settings and reboot. Was "ScaleFactor" removed from your ~/.config/kdeglobals file? If it was not removed, what value was it set to?

3. Do you have a /etc/xdg/kdeglobals file? If you do, can you paste its contents here?
Comment 12 Bug Janitor Service 2023-05-05 03:46:06 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 13 Bug Janitor Service 2023-05-20 03:45:58 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!