Monitor Preferences scaling is not persisted after a reboot (discrete only graphics)

[jwaffe75]

This is a cross post of https://ubuntu-mate.community/t/monitor-preferences-scaling-is-not-persisted-after-a-reboot-discrete-only-graphics/27146

I'm running Debian 12.4.0 with my nvidia GPU in discrete only mode. The discrete only part may be crucial, I went into the BIOS and changed that, the default is hybrid which will use both the intel HD graphics and the nvidia card.

On boot the scaling on my computer (Lenovo P53) seems to be reverted to something scaled down significantly (as in, things are way too big on the screen). This is a pretty high resolution laptop, the default setting for Windows was to do this too.

I can fix this just by going into Monitor Preferences and changing it from auto-detect to 100% or back, but I have to do that every time I turn on the computer. It seems like just changing something and hitting Apply fixes it

Workaround

The permanent fix that's working / persisting seems to be to edit /etc/lightdm/lightdm.conf and put this in it:

[Seat:*]
xserver-command=X -dpi 96

I figured this out by adapting the solution from https://askubuntu.com/a/272172

Steps to reproduce the behaviour

Restart the computer

MATE general version

mate-desktop-environment/stable,now 1.26.0+1 all [installed,automatic]

Package version

mate-control-center/stable,now 1.26.0-2+deb12u1 amd64 [installed,automatic]

Linux Distribution

Debian 12.4.0

Link to bugreport of your Distribution (requirement)

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1063406

[lukefromdc]

That sounds like lightdm is changing your monitor preference. We do not control lightdm, but your saved configuration should be applied on each new session. Not sure where that is stored, I will have to look it up I don't know anything about hybrid graphics though, as I have no such machines.

[jwaffe75]

Hello, thanks for looking at this Could you give me more details about that saved configuration or how it's applied on a new session, so that I can get some clues for what to look at, e.g. - what program applies that configuration - what you mean by "session", is that a lightdm session? An X session? A mate session? - is that configuration the one I've been editing? Would it be one in /etc/ or one that is per user in ~? I'm not afraid of reading C/C++/Python and I'd like to know more but I'm a bit confused by the architecture of the "stack" of lightdm, X, and Mate. Thanks again,

…

On Wednesday, February 7, 2024, Luke from DC ***@***.***> wrote: That sounds like lightdm is changing your monitor preference. We do not control lightdm, but your saved configuration should be applied on each new session. Not sure where that is stored, I will have to look it up I don't know anything about hybrid graphics though, as I have no such machines. — Reply to this email directly, view it on GitHub <#741 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AKGWFUE5HAQJD3PD6QFF63DYSPEBDAVCNFSM6AAAAABC6HB2MWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMZSGY3DINRYGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[lukefromdc]

By session I meant the MATE session only. Some of the Xsession and display manager stuffI really don't know a lot about. Settings are stored ( at least on Debian and Ubuntu as far as I know) it ~.config/monitors.xml

[jwaffe75]

I see, could you give me more information on what a Mate session is?

…

On Saturday, February 10, 2024, Luke from DC ***@***.***> wrote: By session I meant the MATE session only. Some of the Xsession and display manager stuffI really don't know a lot about. Settings are stored ( at least on Debian and Ubuntu as far as I know) it ~.config/monitors.xml — Reply to this email directly, view it on GitHub <#741 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AKGWFUAUF54Y7UC725AUE7DYS64LLAVCNFSM6AAAAABC6HB2MWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMZXGA4TANRXGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[lukefromdc]

When you login from lightdm with MATE selected, what comes up is the MATE session. Logging out ends the session. Killing the xserver also ends the session.

[ivanpu]

I want to provide some more insight into the issue, since I've solved something similar on my end (and satisfyingly enough for me).

First - my issue:
I'm currently (temporary) forced to use a 4k TV as my only monitor.
I too found out that "Scaling" in "Monitor Preferences" doesn't persist for fonts after a reboot, but for me the text is too small to read.
I too use lightdm and NVidia card with proprietary drivers.
What helped me is stumbling upon this comment:
https://ubuntu-mate.community/t/screen-scaling-option/23578/9

Appearance Preferences, Fonts tab, click on Details..., Font Rendering Details - dpi set from 96 to 120

My fix:

1. Fiddle again with "Scaling" in "Monitor Preferences" so the text is readabl.
2. Open that font settings dialog.
3. Realize that DPI field is disabled because "Automatic detection" is enabled.
4. Disabe "Automatic detection" (without modifying the DPI, since it currently looked good).
5. Reboot.

Seems like scaling is finally persisted.

Remaining issue, that I probably wouldn't bother with resolving:

• I do have few seconds during both login and logout that scaling goes crazy in all directions... but I can live with it.
• Mouse pointer is tiny... until I open some window, and then it's getting the pcoper scaling too.
• Lightdm screen is still tiny and unreadable on this TV... but it doesn't hurt my productivity.

Hope this helps.