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#1 2015-11-07 16:21:18

olive
Member
From: Belgium
Registered: 2008-06-22
Posts: 1,490

Wrong dimensions detected by xdpyinfo but xrandr is correct.

The relevant output of xdpyinfo is the following:

  dimensions:    2560x1440 pixels (677x381 millimeters)
  resolution:    96x96 dots per inch

while xrandr gives:

DVI-0 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm

The dimension detected by xrandr are correct, they correspond to the physical dimensions of my monitor. Why is xdpyinfo wrong? From where does it get its info? Because xrandr is correct it cannot be a hardware bug or a problem with EDID. My graphic card is a Radeon HD6750 with the open source ati driver. The problem has been tested with icewm (plain WM that do nothing) as in XFCE. To be honest I have a strange message in the console saying that my EDID checksum is incorrect. But as xrandr gets it right, it cannot be the source of the problem. Moreover 96 dpi is kind of "standard", it seems that xdpyinfo want that and recalculate the dimensions afterwards.

Last edited by olive (2015-11-07 16:36:55)

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#2 2015-11-09 04:21:05

chx
Member
Registered: 2011-05-28
Posts: 101

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.

https://bbs.archlinux.org/viewtopic.php?id=204786 is relevant but contains no solutions.

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#3 2015-11-09 07:16:34

brebs
Member
Registered: 2007-04-03
Posts: 3,742

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.

olive wrote:

in XFCE

See my patch.

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#4 2015-11-09 07:29:48

olive
Member
From: Belgium
Registered: 2008-06-22
Posts: 1,490

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.

Thanks you (chx and brebs) but this appears not really relevant. xdpyinfo report incorrect dimensions: 677x381 millimeters (and so wrong resolution) , but the dimensions reported by xrandr are corrects: 597mm x 336mm. It's true that I normally use XFCE but I have tested it with icewm (plain WM) and the problem persists. xdpyinfo and xrandr are low level tools; they do not depend of GTK3. I have had teh problem for quite some time but did not really made a true effort until now (my real dpi is 110, so it does not make a big difference with 96).

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#5 2017-09-14 20:48:12

dp
Member
From: Zürich, Switzerland
Registered: 2003-05-27
Posts: 3,377
Website

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.

i just switched to some new hardware (lenovo P27) and have seemingly the same issue

graphics is nvidia

EDID info is correct

grep DPI /var/log/Xorg.0.log
[    17.554] (--) NVIDIA(0): DPI set to (162, 161); computed from "UseEdidDpi" X config

xdpyinfo | grep -B2 resolution
screen #0:
  dimensions:    3840x2160 pixels (1016x572 millimeters)
  resolution:    96x96 dots per inch

xrandr
DP-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 596mm x 335mm

using xfce4

did you resolve your issue yet?


The impossible missions are the only ones which succeed.

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#6 2017-09-14 20:52:26

dp
Member
From: Zürich, Switzerland
Registered: 2003-05-27
Posts: 3,377
Website

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.


The impossible missions are the only ones which succeed.

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#7 2017-09-14 20:53:19

dp
Member
From: Zürich, Switzerland
Registered: 2003-05-27
Posts: 3,377
Website

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.

after making xrandr use specific DPI:

xrandr --dpi 170/LVDS

the xdpyinfo is showing the right dimensions ... hmmm

xdpyinfo|grep dimens
  dimensions:    3840x2160 pixels (573x322 millimeters)


The impossible missions are the only ones which succeed.

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#8 2017-09-15 11:25:08

WorMzy
Forum Moderator
From: Scotland
Registered: 2010-06-16
Posts: 10,015
Website

Re: Wrong dimensions detected by xdpyinfo but xrandr is correct.

Please do not necrobump, and use the edit button instead of making multiple posts.

https://wiki.archlinux.org/index.php/Co … bumping.22

Closing.


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