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[On-Topic] any favorite tutorials or other helps for high-DPI monitors?

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  [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2025-12-25 04:15 +0000
    Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 11:45 +0000
      Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2025-12-26 02:03 +0000
    Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? John-Paul Stewart <jpstewart@personalprojects.net> - 2025-12-25 21:38 -0500
      Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2025-12-26 03:55 +0000
        Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? John-Paul Stewart <jpstewart@personalprojects.net> - 2025-12-26 11:10 -0500
          Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2025-12-31 05:00 +0000
      Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? c186282 <c186282@nnada.net> - 2025-12-26 00:03 -0500
      Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2026-01-15 05:09 +0000
        Xorg drivers overriding display resolution (was: Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors?) Nuno Silva <nunojsilva@invalid.invalid> - 2026-01-15 11:20 +0000
      Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2026-01-21 22:54 +0000
        Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Nuno Silva <nunojsilva@invalid.invalid> - 2026-01-22 10:09 +0000
          Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? John-Paul Stewart <jpstewart@personalprojects.net> - 2026-01-22 09:34 -0500
            Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? Robert Riches <spamtrap42@jacob21819.net> - 2026-01-23 04:23 +0000
    Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors? c186282 <c186282@nnada.net> - 2025-12-26 00:00 -0500

#79827 — [On-Topic] any favorite tutorials or other helps for high-DPI monitors?

(In the old days, it was appropriate to tag off-topic posts in
this newsgroup with the bracketed [OT].  Lately, it seems more
appropriate to tag on-topic posts with something.  1/2 :-)

Does anyone have favorite tutorials or other helps for dealing
with a high-DPI transition?

I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
using plain X and fvwm2, no DE as such with 1920x1200 monitors.
Just purchased a round of 4k monitors, so I'll be needing to
adjust xterm fonts, web browser issues, other GUI application
issues, etc.

For web browser issues, I anticipate a lot of fun with websites
and web apps that use (n)px directives for some of their margins
and spacing.  If the browser interprets those at face value,
mixed with other directives in units of text elements and such,
things could end up looking somewhat different from how the
developers intended.

Thanks!

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#79832

On 25/12/2025 04:15, Robert Riches wrote:
> (In the old days, it was appropriate to tag off-topic posts in
> this newsgroup with the bracketed [OT].  Lately, it seems more
> appropriate to tag on-topic posts with something.  1/2 :-)
> 
> Does anyone have favorite tutorials or other helps for dealing
> with a high-DPI transition?
> 
> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
> Just purchased a round of 4k monitors, so I'll be needing to
> adjust xterm fonts, web browser issues, other GUI application
> issues, etc.
> 
> For web browser issues, I anticipate a lot of fun with websites
> and web apps that use (n)px directives for some of their margins
> and spacing.  If the browser interprets those at face value,
> mixed with other directives in units of text elements and such,
> things could end up looking somewhat different from how the
> developers intended.
> 
> Thanks!
> 
Browsers at least will allow you to magnify . Most applications will 
allow a choice of font size and in general desktops can use 
'accessibility' or simply font setups oin menus and borders etc.

-- 
I was brought up to believe that you should never give offence if you 
can avoid it; the new culture tells us you should always take offence if 
you can. There are now experts in the art of taking offence, indeed 
whole academic subjects, such as 'gender studies', devoted to it.

Sir Roger Scruton

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#79849

On 2025-12-25, The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 25/12/2025 04:15, Robert Riches wrote:
>> (In the old days, it was appropriate to tag off-topic posts in
>> this newsgroup with the bracketed [OT].  Lately, it seems more
>> appropriate to tag on-topic posts with something.  1/2 :-)
>> 
>> Does anyone have favorite tutorials or other helps for dealing
>> with a high-DPI transition?
>> 
>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>> Just purchased a round of 4k monitors, so I'll be needing to
>> adjust xterm fonts, web browser issues, other GUI application
>> issues, etc.
>> 
>> For web browser issues, I anticipate a lot of fun with websites
>> and web apps that use (n)px directives for some of their margins
>> and spacing.  If the browser interprets those at face value,
>> mixed with other directives in units of text elements and such,
>> things could end up looking somewhat different from how the
>> developers intended.
>> 
>> Thanks!
>> 
> Browsers at least will allow you to magnify . Most applications will 
> allow a choice of font size and in general desktops can use 
> 'accessibility' or simply font setups oin menus and borders etc.

Thanks!

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#79850

On 2025-12-24 11:15 p.m., Robert Riches wrote:
> 
> Does anyone have favorite tutorials or other helps for dealing
> with a high-DPI transition?
> 
> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
> Just purchased a round of 4k monitors, so I'll be needing to
> adjust xterm fonts, web browser issues, other GUI application
> issues, etc.

It's been a couple years since made a similar switch.  But as far as I
recall, there's not much to do other than configuring X.  I had to
manually specify the monitors' physical size (in millimetres) in my
xorg.conf so that X could calculate the correct DPI.  Then everything
that's measured in points just kind of fell into place.  (E.g., there
was nothing to be done for LibreOffice, etc.)

You'll need to switch your window manager to a high-DPI theme (easy with
my choice, xfwm4) since that's all laid out in pixels and you'll have
tiny icons and title bars if you don't change.

There were very few apps that required any tweaking once X and the
window manager were correctly configured.  The venerable 'gv' is the
only one I can think of that required its own DPI setting (in
~/.Xresources) rather than using X's own.

> For web browser issues, I anticipate a lot of fun with websites
> and web apps that use (n)px directives for some of their margins
> and spacing.  If the browser interprets those at face value,
> mixed with other directives in units of text elements and such,
> things could end up looking somewhat different from how the
> developers intended.
That's actually not an issue.  HTML/CSS "px" are NOT device pixels but
units of 1/96 inches.[1]  In other words, HTML/CSS "px" are standardized
at 96 DPI regardless of actual screen resolution.  So if something
specifies 24px it actually means 1/4 inch.  On my 4K displays that ends
up being more like 40 device pixels.  So websites will still work more
or less as expected.

[1] https://www.w3schools.com/css/css_units.asp

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#79852

On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>> 
>> Does anyone have favorite tutorials or other helps for dealing
>> with a high-DPI transition?
>> 
>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>> Just purchased a round of 4k monitors, so I'll be needing to
>> adjust xterm fonts, web browser issues, other GUI application
>> issues, etc.
>
> It's been a couple years since made a similar switch.  But as far as I
> recall, there's not much to do other than configuring X.  I had to
> manually specify the monitors' physical size (in millimetres) in my
> xorg.conf so that X could calculate the correct DPI.  Then everything
> that's measured in points just kind of fell into place.  (E.g., there
> was nothing to be done for LibreOffice, etc.)

And, it appears running 'xdpyinfo | grep resolution' should tell
me whether X automagically caught the resolution in case that's
already taken care of.

> You'll need to switch your window manager to a high-DPI theme (easy with
> my choice, xfwm4) since that's all laid out in pixels and you'll have
> tiny icons and title bars if you don't change.

Good points.  I don't intentionally use icons, and when I
accidentally iconify something it doesn't much matter what size
it is, because all I'm going to do is deiconify it.  Title bars
might be taken care of by the xterm*TitleFont and similar, so
I'll test that.

Finding a new fixed-width font could be an adventure.  I have
been using '9x15' for pretty much everything, but scaling says
I'll need approximately 15 or 16 by about 26, and I don't think
there is a canned one of that size.  Trying to use xfontsel has
always been about as much fun as battling a hydra.

> There were very few apps that required any tweaking once X and the
> window manager were correctly configured.  The venerable 'gv' is the
> only one I can think of that required its own DPI setting (in
> ~/.Xresources) rather than using X's own.

Thanks for the tip about gv.

>> For web browser issues, I anticipate a lot of fun with websites
>> and web apps that use (n)px directives for some of their margins
>> and spacing.  If the browser interprets those at face value,
>> mixed with other directives in units of text elements and such,
>> things could end up looking somewhat different from how the
>> developers intended.
> That's actually not an issue.  HTML/CSS "px" are NOT device pixels but
> units of 1/96 inches.[1]  In other words, HTML/CSS "px" are standardized
> at 96 DPI regardless of actual screen resolution.  So if something
> specifies 24px it actually means 1/4 inch.  On my 4K displays that ends
> up being more like 40 device pixels.  So websites will still work more
> or less as expected.
>
> [1] https://www.w3schools.com/css/css_units.asp

SWEET!  Thanks for explaining that HTML/CSS "px" are their own
thing, independent of device pixels!  Link bookmarked and your
post printed (so I can see it even if the screen is unreadable at
some point during the journey).

Thank you!

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#79869

On 2025-12-25 10:55 p.m., Robert Riches wrote:
> On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
>>
>> It's been a couple years since made a similar switch.  But as far as I
>> recall, there's not much to do other than configuring X.  I had to
>> manually specify the monitors' physical size (in millimetres) in my
>> xorg.conf so that X could calculate the correct DPI.  Then everything
>> that's measured in points just kind of fell into place.  (E.g., there
>> was nothing to be done for LibreOffice, etc.)
> 
> And, it appears running 'xdpyinfo | grep resolution' should tell
> me whether X automagically caught the resolution in case that's
> already taken care of.

Correct.  It was mis-detected with my monitors so manual intervention
was necessary.  I hope you have better luck with the automagic stuff!

>> You'll need to switch your window manager to a high-DPI theme (easy with
>> my choice, xfwm4) since that's all laid out in pixels and you'll have
>> tiny icons and title bars if you don't change.
> 
> Good points.  I don't intentionally use icons, and when I
> accidentally iconify something it doesn't much matter what size
> it is, because all I'm going to do is deiconify it.  Title bars
> might be taken care of by the xterm*TitleFont and similar, so
> I'll test that.

Sorry, I wasn't clear there.  I was referring to the minimize, maximize,
etc. icons in the window's title bar.  Not the ones you get from iconifying.

> Finding a new fixed-width font could be an adventure.  I have
> been using '9x15' for pretty much everything, but scaling says
> I'll need approximately 15 or 16 by about 26, and I don't think
> there is a canned one of that size.  Trying to use xfontsel has
> always been about as much fun as battling a hydra.

I use the 12x24 font on my 4K monitors.  Perhaps that will be close
enough for your size requirements.

I'm also a fan of the terminus fixed-width font.  On Debian you can
install the xfonts-terminus package.  It's available in 24 or 28 pixel
high versions (among others) through xfontsel.

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#80153

On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
> On 2025-12-25 10:55 p.m., Robert Riches wrote:
>> On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
>>>
>>> It's been a couple years since made a similar switch.  But as far as I
>>> recall, there's not much to do other than configuring X.  I had to
>>> manually specify the monitors' physical size (in millimetres) in my
>>> xorg.conf so that X could calculate the correct DPI.  Then everything
>>> that's measured in points just kind of fell into place.  (E.g., there
>>> was nothing to be done for LibreOffice, etc.)
>> 
>> And, it appears running 'xdpyinfo | grep resolution' should tell
>> me whether X automagically caught the resolution in case that's
>> already taken care of.
>
> Correct.  It was mis-detected with my monitors so manual intervention
> was necessary.  I hope you have better luck with the automagic stuff!
>
>>> You'll need to switch your window manager to a high-DPI theme (easy with
>>> my choice, xfwm4) since that's all laid out in pixels and you'll have
>>> tiny icons and title bars if you don't change.
>> 
>> Good points.  I don't intentionally use icons, and when I
>> accidentally iconify something it doesn't much matter what size
>> it is, because all I'm going to do is deiconify it.  Title bars
>> might be taken care of by the xterm*TitleFont and similar, so
>> I'll test that.
>
> Sorry, I wasn't clear there.  I was referring to the minimize, maximize,
> etc. icons in the window's title bar.  Not the ones you get from iconifying.
>
>> Finding a new fixed-width font could be an adventure.  I have
>> been using '9x15' for pretty much everything, but scaling says
>> I'll need approximately 15 or 16 by about 26, and I don't think
>> there is a canned one of that size.  Trying to use xfontsel has
>> always been about as much fun as battling a hydra.
>
> I use the 12x24 font on my 4K monitors.  Perhaps that will be close
> enough for your size requirements.
>
> I'm also a fan of the terminus fixed-width font.  On Debian you can
> install the xfonts-terminus package.  It's available in 24 or 28 pixel
> high versions (among others) through xfontsel.

Thanks again!

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#79854

On 12/25/25 21:38, John-Paul Stewart wrote:
> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>>
>> Does anyone have favorite tutorials or other helps for dealing
>> with a high-DPI transition?
>>
>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>> Just purchased a round of 4k monitors, so I'll be needing to
>> adjust xterm fonts, web browser issues, other GUI application
>> issues, etc.
> 
> It's been a couple years since made a similar switch.  But as far as I
> recall, there's not much to do other than configuring X.  I had to
> manually specify the monitors' physical size (in millimetres) in my
> xorg.conf so that X could calculate the correct DPI.  Then everything
> that's measured in points just kind of fell into place.  (E.g., there
> was nothing to be done for LibreOffice, etc.)

   Ha ... yea ... I remember installing 'X' on a very
   early RedHat. Tons of manual tweaks - with LOTS of
   guessing and fails - involved there. It was a good
   day before I got the damned mouse to work right  :-)

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#81138

On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>> 
>> Does anyone have favorite tutorials or other helps for dealing
>> with a high-DPI transition?
>> 
>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>> Just purchased a round of 4k monitors, so I'll be needing to
>> adjust xterm fonts, web browser issues, other GUI application
>> issues, etc.
>
> It's been a couple years since made a similar switch.  But as far as I
> recall, there's not much to do other than configuring X.  I had to
> manually specify the monitors' physical size (in millimetres) in my
> xorg.conf so that X could calculate the correct DPI.  Then everything
> that's measured in points just kind of fell into place.  (E.g., there
> was nothing to be done for LibreOffice, etc.)

After waiting for adapters to arrive (by "super saver" shipping)
and getting the 1.1GB system logs after physically installing the
4K monitors, I got them running at 1920x1200 by putting
"xrandr --output ... --mode 1920x1200" and a couple of sleep
commands in my .Xclients file.  Omitting the xrandr commands
brings up X in 3840x2160 mode, but the DPI is stuck at 96.

Xorg.0.log showed the EDID size information being fetched correct
as 597 x 336 mm.  However, Xorg.0.log showed the DPI being set to
(96, 96).

So, I created an xorg.conf.  Evidently, X11 wants things
specified in terms of two monitors side by side--thus the 1194 by
336.  After some experimenting, I put this in /etc/X11/xorg.conf:

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv cut here vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Section "Screen"
  Identifier "Default Screen Section"
  Monitor "Asus PA279CV"
EndSection

Section "Monitor"
  Identifier "Asus PA279CV"
  VendorName "Asus"
  ModelName "PA279CV"
  DisplaySize 1194 336
EndSection
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cut here ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

With that, grepping /var/log/Xorg.0.log for words EDID, mm, and
DPI yields this:

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv cut here vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
[179297.003] (II) AMDGPU(0): EDID for output DisplayPort-0
[179297.003] (II) AMDGPU(0): EDID Version: 1.3
[179297.003] (II) AMDGPU(0): clock: 594.0 MHz   Image Size:  597 x 336 mm
[179297.003] (II) AMDGPU(0): clock: 148.5 MHz   Image Size:  597 x 336 mm
[179297.003] (II) AMDGPU(0): clock: 297.0 MHz   Image Size:  597 x 336 mm
[179297.003] (II) AMDGPU(0): clock: 241.5 MHz   Image Size:  597 x 336 mm
[179297.003] (II) AMDGPU(0): Number of EDID sections to follow: 1
[179297.003] (II) AMDGPU(0): EDID (in hex):
[179297.006] (II) AMDGPU(0): EDID for output DisplayPort-1
[179297.006] (II) AMDGPU(0): EDID Version: 1.3
[179297.007] (II) AMDGPU(0): clock: 594.0 MHz   Image Size:  597 x 336 mm
[179297.007] (II) AMDGPU(0): clock: 148.5 MHz   Image Size:  597 x 336 mm
[179297.007] (II) AMDGPU(0): clock: 297.0 MHz   Image Size:  597 x 336 mm
[179297.007] (II) AMDGPU(0): clock: 241.5 MHz   Image Size:  597 x 336 mm
[179297.007] (II) AMDGPU(0): Number of EDID sections to follow: 1
[179297.007] (II) AMDGPU(0): EDID (in hex):
[179297.007] (II) AMDGPU(0): EDID for output DisplayPort-2
[179297.007] (II) AMDGPU(0): EDID for output HDMI-A-0
[179297.007] (**) AMDGPU(0): Display dimensions: (1194, 336) mm
[179297.007] (**) AMDGPU(0): DPI set to (163, 163)
[179297.465] (II) event6  - Logitech Trackball: device set to 300 DPI
[179297.561] (II) event6  - Logitech Trackball: device set to 300 DPI
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cut here ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The (163, 163) is the correct DPI figure.  An earlier DisplaySize
value of 597 336 had yielded a DPI figure of (326, 163).  With
either of the DisplaySize values, and even with Xorg.0.log
showing the correct DPI, xdpyinfo still reports DPI as 96x96.

So, it appears that even when Xorg.0.log is showing the correct
DPI, but there's apparently a disconnect between that and
xdpyinfo.

Any suggestions?  Thanks in advance!

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#81147 — Xorg drivers overriding display resolution (was: Re: [On-Topic] any favorite tutorials or other helps for high-DPI monitors?)

On 2026-01-15, Robert Riches wrote:

> On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
>> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>>> 
>>> Does anyone have favorite tutorials or other helps for dealing
>>> with a high-DPI transition?
>>> 
>>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>>> Just purchased a round of 4k monitors, so I'll be needing to
>>> adjust xterm fonts, web browser issues, other GUI application
>>> issues, etc.
>>
>> It's been a couple years since made a similar switch.  But as far as I
>> recall, there's not much to do other than configuring X.  I had to
>> manually specify the monitors' physical size (in millimetres) in my
>> xorg.conf so that X could calculate the correct DPI.  Then everything
>> that's measured in points just kind of fell into place.  (E.g., there
>> was nothing to be done for LibreOffice, etc.)
>
> After waiting for adapters to arrive (by "super saver" shipping)
> and getting the 1.1GB system logs after physically installing the
> 4K monitors, I got them running at 1920x1200 by putting
> "xrandr --output ... --mode 1920x1200" and a couple of sleep
> commands in my .Xclients file.  Omitting the xrandr commands
> brings up X in 3840x2160 mode, but the DPI is stuck at 96.
>
> Xorg.0.log showed the EDID size information being fetched correct
> as 597 x 336 mm.  However, Xorg.0.log showed the DPI being set to
> (96, 96).
>
> So, I created an xorg.conf.  Evidently, X11 wants things
> specified in terms of two monitors side by side--thus the 1194 by
> 336.  After some experimenting, I put this in /etc/X11/xorg.conf:
>
> vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv cut here vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
> Section "Screen"
>   Identifier "Default Screen Section"
>   Monitor "Asus PA279CV"
> EndSection
>
> Section "Monitor"
>   Identifier "Asus PA279CV"
>   VendorName "Asus"
>   ModelName "PA279CV"
>   DisplaySize 1194 336
> EndSection
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cut here ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> With that, grepping /var/log/Xorg.0.log for words EDID, mm, and
> DPI yields this:
>
> vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv cut here vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
> [179297.003] (II) AMDGPU(0): EDID for output DisplayPort-0
> [179297.003] (II) AMDGPU(0): EDID Version: 1.3
> [179297.003] (II) AMDGPU(0): clock: 594.0 MHz   Image Size:  597 x 336 mm
> [179297.003] (II) AMDGPU(0): clock: 148.5 MHz   Image Size:  597 x 336 mm
> [179297.003] (II) AMDGPU(0): clock: 297.0 MHz   Image Size:  597 x 336 mm
> [179297.003] (II) AMDGPU(0): clock: 241.5 MHz   Image Size:  597 x 336 mm
> [179297.003] (II) AMDGPU(0): Number of EDID sections to follow: 1
> [179297.003] (II) AMDGPU(0): EDID (in hex):
> [179297.006] (II) AMDGPU(0): EDID for output DisplayPort-1
> [179297.006] (II) AMDGPU(0): EDID Version: 1.3
> [179297.007] (II) AMDGPU(0): clock: 594.0 MHz   Image Size:  597 x 336 mm
> [179297.007] (II) AMDGPU(0): clock: 148.5 MHz   Image Size:  597 x 336 mm
> [179297.007] (II) AMDGPU(0): clock: 297.0 MHz   Image Size:  597 x 336 mm
> [179297.007] (II) AMDGPU(0): clock: 241.5 MHz   Image Size:  597 x 336 mm
> [179297.007] (II) AMDGPU(0): Number of EDID sections to follow: 1
> [179297.007] (II) AMDGPU(0): EDID (in hex):
> [179297.007] (II) AMDGPU(0): EDID for output DisplayPort-2
> [179297.007] (II) AMDGPU(0): EDID for output HDMI-A-0
> [179297.007] (**) AMDGPU(0): Display dimensions: (1194, 336) mm
> [179297.007] (**) AMDGPU(0): DPI set to (163, 163)
> [179297.465] (II) event6  - Logitech Trackball: device set to 300 DPI
> [179297.561] (II) event6  - Logitech Trackball: device set to 300 DPI
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cut here ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> The (163, 163) is the correct DPI figure.  An earlier DisplaySize
> value of 597 336 had yielded a DPI figure of (326, 163).  With
> either of the DisplaySize values, and even with Xorg.0.log
> showing the correct DPI, xdpyinfo still reports DPI as 96x96.
>
> So, it appears that even when Xorg.0.log is showing the correct
> DPI, but there's apparently a disconnect between that and
> xdpyinfo.
>
> Any suggestions?  Thanks in advance!

I've seen this happen with radeon (the driver), logs showed the correct
information being retrieved via EDID, and then the resolution would be
reverted to some hardcoded 96.

For that reason, I've had either

    xrandr --dpi VALUE

or
    xrandr --dpi OUTPUT_NAME

in .xinitrc, to either force a specific DPI value or get it set again
from EDID information from the named output.

I think I never got around to figure out why is the driver - or some
other piece? - apparently overriding the EDID resolution like this
(makes one wonder if remarks about X11 not handling "hi-dpi" well could
be in part due to this nowadays... after all under X11 one could use
different resolutions two decades ago already).

-- 
Nuno Silva

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#81450

On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>> 
>> Does anyone have favorite tutorials or other helps for dealing
>> with a high-DPI transition?
>> 
>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>> Just purchased a round of 4k monitors, so I'll be needing to
>> adjust xterm fonts, web browser issues, other GUI application
>> issues, etc.
>
> It's been a couple years since made a similar switch.  But as far as I
> recall, there's not much to do other than configuring X.  I had to
> manually specify the monitors' physical size (in millimetres) in my
> xorg.conf so that X could calculate the correct DPI.  Then everything
> that's measured in points just kind of fell into place.  (E.g., there
> was nothing to be done for LibreOffice, etc.)
>
> You'll need to switch your window manager to a high-DPI theme (easy with
> my choice, xfwm4) since that's all laid out in pixels and you'll have
> tiny icons and title bars if you don't change.
>
> There were very few apps that required any tweaking once X and the
> window manager were correctly configured.  The venerable 'gv' is the
> only one I can think of that required its own DPI setting (in
> ~/.Xresources) rather than using X's own.
>
>> For web browser issues, I anticipate a lot of fun with websites
>> and web apps that use (n)px directives for some of their margins
>> and spacing.  If the browser interprets those at face value,
>> mixed with other directives in units of text elements and such,
>> things could end up looking somewhat different from how the
>> developers intended.
> That's actually not an issue.  HTML/CSS "px" are NOT device pixels but
> units of 1/96 inches.[1]  In other words, HTML/CSS "px" are standardized
> at 96 DPI regardless of actual screen resolution.  So if something
> specifies 24px it actually means 1/4 inch.  On my 4K displays that ends
> up being more like 40 device pixels.  So websites will still work more
> or less as expected.
>
> [1] https://www.w3schools.com/css/css_units.asp

For anyone finding this thread in the future, there's another
trick for Firefox.  In about:config, set

        layout.css.devPixelsPerPx

to a value greater than 1.  For a 27" 4K monitor, the monitor's
device DPI is 163, and a value of 1.6 makes the Firefox UI
elements (menu bar, dialogs, etc.) a reasonable size.  YMMV on
the value for your situation.

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#81477

On 2026-01-21, Robert Riches wrote:

> On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
>> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>>> 
>>> Does anyone have favorite tutorials or other helps for dealing
>>> with a high-DPI transition?
>>> 
>>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>>> Just purchased a round of 4k monitors, so I'll be needing to
>>> adjust xterm fonts, web browser issues, other GUI application
>>> issues, etc.
>>
>> It's been a couple years since made a similar switch.  But as far as I
>> recall, there's not much to do other than configuring X.  I had to
>> manually specify the monitors' physical size (in millimetres) in my
>> xorg.conf so that X could calculate the correct DPI.  Then everything
>> that's measured in points just kind of fell into place.  (E.g., there
>> was nothing to be done for LibreOffice, etc.)
>>
>> You'll need to switch your window manager to a high-DPI theme (easy with
>> my choice, xfwm4) since that's all laid out in pixels and you'll have
>> tiny icons and title bars if you don't change.
>>
>> There were very few apps that required any tweaking once X and the
>> window manager were correctly configured.  The venerable 'gv' is the
>> only one I can think of that required its own DPI setting (in
>> ~/.Xresources) rather than using X's own.
>>
>>> For web browser issues, I anticipate a lot of fun with websites
>>> and web apps that use (n)px directives for some of their margins
>>> and spacing.  If the browser interprets those at face value,
>>> mixed with other directives in units of text elements and such,
>>> things could end up looking somewhat different from how the
>>> developers intended.
>> That's actually not an issue.  HTML/CSS "px" are NOT device pixels but
>> units of 1/96 inches.[1]  In other words, HTML/CSS "px" are standardized
>> at 96 DPI regardless of actual screen resolution.  So if something
>> specifies 24px it actually means 1/4 inch.  On my 4K displays that ends
>> up being more like 40 device pixels.  So websites will still work more
>> or less as expected.
>>
>> [1] https://www.w3schools.com/css/css_units.asp
>
> For anyone finding this thread in the future, there's another
> trick for Firefox.  In about:config, set
>
>         layout.css.devPixelsPerPx
>
> to a value greater than 1.  For a 27" 4K monitor, the monitor's
> device DPI is 163, and a value of 1.6 makes the Firefox UI
> elements (menu bar, dialogs, etc.) a reasonable size.  YMMV on
> the value for your situation.

IIRC there was a value that would make it get the resolution from the
platform. But on Linux this may require GTK+ to also honor the
resolution...

Ah, it was 0 on layout.css.dpi, but this was probably at a time when the
setting you mention did *not* affect Firefox's UI:

https://wiki.archlinux.org/title/Firefox/Tweaks#Configure_the_DPI_value

https://kb.mozillazine.org/Layout.css.dpi

-- 
Nuno Silva

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#81494

On 2026-01-22 5:09 a.m., Nuno Silva wrote:
> On 2026-01-21, Robert Riches wrote:
> 
>> On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
>>> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>>>>
>>>> Does anyone have favorite tutorials or other helps for dealing
>>>> with a high-DPI transition?
>>>>
>>>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>>>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>>>> Just purchased a round of 4k monitors, so I'll be needing to
>>>> adjust xterm fonts, web browser issues, other GUI application
>>>> issues, etc.
>>>
>>> It's been a couple years since made a similar switch.  But as far as I
>>> recall, there's not much to do other than configuring X.  I had to
>>> manually specify the monitors' physical size (in millimetres) in my
>>> xorg.conf so that X could calculate the correct DPI.  Then everything
>>> that's measured in points just kind of fell into place.  (E.g., there
>>> was nothing to be done for LibreOffice, etc.)
>>>
>>> You'll need to switch your window manager to a high-DPI theme (easy with
>>> my choice, xfwm4) since that's all laid out in pixels and you'll have
>>> tiny icons and title bars if you don't change.
>>>
>>> There were very few apps that required any tweaking once X and the
>>> window manager were correctly configured.  The venerable 'gv' is the
>>> only one I can think of that required its own DPI setting (in
>>> ~/.Xresources) rather than using X's own.
>>>
>>>> For web browser issues, I anticipate a lot of fun with websites
>>>> and web apps that use (n)px directives for some of their margins
>>>> and spacing.  If the browser interprets those at face value,
>>>> mixed with other directives in units of text elements and such,
>>>> things could end up looking somewhat different from how the
>>>> developers intended.
>>> That's actually not an issue.  HTML/CSS "px" are NOT device pixels but
>>> units of 1/96 inches.[1]  In other words, HTML/CSS "px" are standardized
>>> at 96 DPI regardless of actual screen resolution.  So if something
>>> specifies 24px it actually means 1/4 inch.  On my 4K displays that ends
>>> up being more like 40 device pixels.  So websites will still work more
>>> or less as expected.
>>>
>>> [1] https://www.w3schools.com/css/css_units.asp
>>
>> For anyone finding this thread in the future, there's another
>> trick for Firefox.  In about:config, set
>>
>>         layout.css.devPixelsPerPx
>>
>> to a value greater than 1.  For a 27" 4K monitor, the monitor's
>> device DPI is 163, and a value of 1.6 makes the Firefox UI
>> elements (menu bar, dialogs, etc.) a reasonable size.  YMMV on
>> the value for your situation.
> 
> IIRC there was a value that would make it get the resolution from the
> platform. 
Yes.  On my system layout.css.devPixelsPerPx is set to -1.0 which means
Firefox will get the value from the system and everything works as
expected. (I'm also using a 27" 4K monitor at 163 DPI like the previous
poster.)

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#81529

On 2026-01-22, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
> On 2026-01-22 5:09 a.m., Nuno Silva wrote:
>> On 2026-01-21, Robert Riches wrote:
>> 
>>> On 2025-12-26, John-Paul Stewart <jpstewart@personalprojects.net> wrote:
>>>> On 2025-12-24 11:15 p.m., Robert Riches wrote:
>>>>>
>>>>> Does anyone have favorite tutorials or other helps for dealing
>>>>> with a high-DPI transition?
>>>>>
>>>>> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
>>>>> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
>>>>> Just purchased a round of 4k monitors, so I'll be needing to
>>>>> adjust xterm fonts, web browser issues, other GUI application
>>>>> issues, etc.
>>>>
>>>> It's been a couple years since made a similar switch.  But as far as I
>>>> recall, there's not much to do other than configuring X.  I had to
>>>> manually specify the monitors' physical size (in millimetres) in my
>>>> xorg.conf so that X could calculate the correct DPI.  Then everything
>>>> that's measured in points just kind of fell into place.  (E.g., there
>>>> was nothing to be done for LibreOffice, etc.)
>>>>
>>>> You'll need to switch your window manager to a high-DPI theme (easy with
>>>> my choice, xfwm4) since that's all laid out in pixels and you'll have
>>>> tiny icons and title bars if you don't change.
>>>>
>>>> There were very few apps that required any tweaking once X and the
>>>> window manager were correctly configured.  The venerable 'gv' is the
>>>> only one I can think of that required its own DPI setting (in
>>>> ~/.Xresources) rather than using X's own.
>>>>
>>>>> For web browser issues, I anticipate a lot of fun with websites
>>>>> and web apps that use (n)px directives for some of their margins
>>>>> and spacing.  If the browser interprets those at face value,
>>>>> mixed with other directives in units of text elements and such,
>>>>> things could end up looking somewhat different from how the
>>>>> developers intended.
>>>> That's actually not an issue.  HTML/CSS "px" are NOT device pixels but
>>>> units of 1/96 inches.[1]  In other words, HTML/CSS "px" are standardized
>>>> at 96 DPI regardless of actual screen resolution.  So if something
>>>> specifies 24px it actually means 1/4 inch.  On my 4K displays that ends
>>>> up being more like 40 device pixels.  So websites will still work more
>>>> or less as expected.
>>>>
>>>> [1] https://www.w3schools.com/css/css_units.asp
>>>
>>> For anyone finding this thread in the future, there's another
>>> trick for Firefox.  In about:config, set
>>>
>>>         layout.css.devPixelsPerPx
>>>
>>> to a value greater than 1.  For a 27" 4K monitor, the monitor's
>>> device DPI is 163, and a value of 1.6 makes the Firefox UI
>>> elements (menu bar, dialogs, etc.) a reasonable size.  YMMV on
>>> the value for your situation.
>> 
>> IIRC there was a value that would make it get the resolution from the
>> platform. 
> Yes.  On my system layout.css.devPixelsPerPx is set to -1.0 which means
> Firefox will get the value from the system and everything works as
> expected. (I'm also using a 27" 4K monitor at 163 DPI like the previous
> poster.)

-1.0 is what mine had layout.css.devPixelsPerPx set to, as well.
 It was not getting the DPI/resolution from the system.  xdpyinfo
 reports a resolution of 163dpi.

Setting layout.css.devPixelsPerPx to 1.7 shows web page content
at (as far as I could see) the same as zooming to 170%.  Setting
the variable made the menubar, dialogs, etc. reasonably sized,
too.

-- 
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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#79853

On 12/24/25 23:15, Robert Riches wrote:
> (In the old days, it was appropriate to tag off-topic posts in
> this newsgroup with the bracketed [OT].  Lately, it seems more
> appropriate to tag on-topic posts with something.  1/2 :-)
> 
> Does anyone have favorite tutorials or other helps for dealing
> with a high-DPI transition?
> 
> I'm Running Devuan (currently Daedalus, hopefully soon Excalibur)
> using plain X and fvwm2, no DE as such with 1920x1200 monitors.
> Just purchased a round of 4k monitors, so I'll be needing to
> adjust xterm fonts, web browser issues, other GUI application
> issues, etc.
> 
> For web browser issues, I anticipate a lot of fun with websites
> and web apps that use (n)px directives for some of their margins
> and spacing.  If the browser interprets those at face value,
> mixed with other directives in units of text elements and such,
> things could end up looking somewhat different from how the
> developers intended.
> 
> Thanks!
> 

   NO ! NO ! Not an ON TOPIC post !!!  :-)

   As for the info you need ... I've had similar issues
   and found that it's not all concentrated in one place,
   or fully ACCURATE anywhere. Sorry, no 'perfect tutorial',
   and FORGET the terse incomprehensible 'X' docs ... those
   seem to be writ for a different kind of human than I.

   As for 'off topic' ... that's partially MY fault. COSLM
   was dying, it'd be like days between posts. Seen that
   before. Sometimes there just isn't much new to SAY about
   Linux alas.

   In my defense, I DO try to weave a little Linux-related
   stuff into the off-topics at some place or another ...

   'AI', while it seems off-topic, really isn't. Not sure
   if Linux/UNIX will be around in a decade. Looks like
   it will all be "AI-OS", 95% off-machine. Yer boxes
   will be naught but thin clients with all else being
   done by a remote "AI" ... well or not so well ... and
   DO expect to PAY for it. Hell, 'AI' will even do all
   the app development/programming - that capability
   is being demonstrated even now and will be fully
   refined in just a few years.

   Good ? Well ... a little good, a lot of not-so-good.
   However since TRILLIONS have been invested in 'AI'
   this IS how it's gonna go.

   An interesting meta view ... humans soon won't be able
   to figure out the 'AI'-generated code, I can envision
   it having its own ultra-compacted language, then further
   refined/compacted by the AIs themselves. At that point
   software/systems become "magic" ... back to dark-ages
   thinking  :-)

   The AIs become 'god' - running EVERYTHING - and we will
   not have a CLUE about why/how or future directions.

   Did it to ourselves ..........

   As for "X" ... basically you install xorg. It is
   'automatic' enough at this point to find/recognize
   video displays and at least do the default settings.
   Kind of the same with "Wayland", but it's not as
   refined as "X" nor as well documented. Any modern
   DE will have GUI means for tweaking the video.

   There IS a place for Linux units without a GUI ...
   mostly 'servers' and dedicated routers (and for
   the SERIOUSLY retro-minded). However GUIs let
   you set LOTS of config files all at once with
   just a click - huge time/mistake saver. An alt
   is to not enable the GUI at boot ... require it
   to be manually started over SSH or such. That
   way you have it IF/WHEN you needed it.

   DE ? I favor 'simple - no BS', thus LXDE or XFCE.

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