Mailinglist Archive: opensuse-factory (536 mails)

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Re: [opensuse-factory] Leap 15.0: Scaling issues under X
  • From: Bruno Friedmann <bruno@xxxxxxxxxxx>
  • Date: Tue, 22 May 2018 16:42:44 +0200
  • Message-id: <2561114.Rh6IC2rCHk@qt-kt>
On mardi, 22 mai 2018 16.18:54 h CEST Michal Srb wrote:
On úterý 22. května 2018 15:50:41 CEST Till Dörges wrote:
Hi all,

I'm just giving Leap 15.0 a try.

I noticed that using KDE/plasma both fonts and GUI elements are scaled way
too big for my current setup.

It may be related to changes done because of this bug:
https://bugzilla.opensuse.org/show_bug.cgi?id=1089932

Basically there is long disagreement (lasting many years now) between X
developers and application developers on where should applications get
information about DPI and whether there should be some single DPI value
somehow combined from all connected monitors.

X used to provide a single DPI value, but single value no longer makes sense
with multiple monitors. Plus there was no way to notify applications about
the value changing. So this value is now deprecated and always set to 96
DPI. It can not be completely removed because it is part of the X protocol.
Instead X provides DPI for individual monitors and can notify applications
when the situation changes.

Qt needs some single DPI value on start. In that bug Qt was changed to stop
using this always-96DPI value and instead use the DPI of the primary
monitor.
My current setup is a notebook (lid closed) with an external monitor.
Monitor has a resolution of 1920x1200. Graphics adapater is an "nVidia
GM107GLM [Quadro M1200 Mobile]".

Your external monitor does not seem to be high-DPI. When you use it, is it
set as primary? Could you attach output of xrandr?

Michal

I share your pain, I've the situation where my internal lcd is hidpi
3840x2160@288dpi my primary external 27" also hidpi 3840x2160 but @163dpi
and the second external 24" monitor full hd at 1920x1080 @ 96 dpi....

I was playing with /etc/X11/xorg.conf.d/50-devices.conf

Can be used to tell nvidia to not use any ediddpi data pick from monitor
Work well with a average or fixed dpi that "works" on all
Option "UseEdidDpi" "false"
Option "DPI" "192x192"

You can also used a prefered monitor (but beware you will have to change it
when only you lcd is used)

Option "UseEdidDpi" "DFP-4"

Can be changed if useful (but doesn't seems to be supported by nvidia)
Option "ConstantDPI" "true"



--

Bruno Friedmann
Ioda-Net Sàrl www.ioda-net.ch
Bareos Partner, openSUSE Member, fsfe supporter
GPG KEY : D5C9B751C4653227
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