#xorg-devel log about forced 96dpi

#xorg-devel at Sat Jun 22 12:37:21 FET 2013
* Topic: all support questions: #xorg | xorg-server 1.15 merge window open! | Sign up now to join us at XDC 2013: Sept 23-25, Portland, Oregon, USA - http://wiki.x.org/wiki/Events/XDC2013
* Topic set by alanc!~alanc@inet-hqmc01-o.oracle.com at Thu Jun 20 23:52:09 2013
<alesguzik> hi
<alesguzik> My dpi is not set up correctly.
<alesguzik> I found this https://bugs.freedesktop.org/show_bug.cgi?id=23705 , which says forced 96dpi is as expected
<alesguzik> And I can understand why this might be a point
<alesguzik> But I also found this https://bugs.freedesktop.org/show_bug.cgi?id=41115
<alesguzik> about implementing configuration option
<alesguzik> to not force 96 dpi
<alesguzik> It even has patches
<alesguzik> It's almost 2 years since then and it's still not accepted
<alesguzik> Are there any problems with patch? Or anything else?
<alesguzik> How this could be fixed?
<ohsix> not a lot of people are bothered, since getting the per display dpi right is a hard problem, even if you can set it for one single monitor in particular, 'fixed' is handling some difference in dpi across displays, which doesn't happen in the toolkits or anything
<ohsix> also, you use randr
<alesguzik> I'm not asking about making it default, but when screen size can be detected and resolution is known, what is the problem with dpi?
<alesguzik> It worked at some point in the past
<ohsix> it never worked
<alesguzik> between 1.6.3 and 1.7, I think. It is mentioned it the first lines of first bugreport
<alesguzik> *mentioned in
<alesguzik> and what is the problem with randr?
<alesguzik> *with me using randr
<ohsix> the 'when' is the hard part, you get the information from the edid and it's wrong, when it's wrong things that are dpi sensitive are cartoonishly wrong
<ohsix> there's a protocol dpi that's not sufficient for this, that's the one you can't change
<ohsix> randr can know the screen size, and it's per connection/output, so you set it there
<alesguzik> Am I understand correctly that correct dpi may be set correctly only when randr is used?
<alesguzik> * that dpi
<alesguzik> are there ways to set dpi via randr at server start and not via .xinitrc?
<KiBi> man/Xserver.man:.B \-dpi \fIresolution\fP
<KiBi> os/utils.c:        else if (strcmp(argv[i], "-dpi") == 0) {
<alesguzik> KiBi: -dpi sets fixed resolution, but I want it autodetected depending on the monitor used
<alesguzik> * s/resolution/dpi/
<ohsix> then you want a desktop widget that does it :> like gnome-settings-daemon
<alesguzik> I don't use not gnome nor kde
<alesguzik> Just tiling window manager
<alesguzik> CLFSWM, to be precise
<ohsix> maybe you misunderstood me, i was telling you what's expected to do it, and something that does; what you are using that lacks it isn't a very valuable thing to know
<ohsix> any cobbled together thing where nobody really cares is going to miss details like that
<alesguzik> are you about xorg or my window manager? window manager is not supposed to do things like setting dpi
<alesguzik> it just have to manage windows
<ohsix> so you did misunderstand, find something that talks to xrandr for you to set your preferences at the appropriate time, since you do not have such a thing
<alesguzik> so if gnome-settings-daemon sets dpi after server was started, I think setting it in .xinitrc is really correct way to go
<alesguzik> got it
<alesguzik> ok, thanks
<ohsix> and your wm does need to know where windows are, dpi is just one aspect, i'm guessing you expect it to do something when a monitor is plugged in
<alesguzik> it uses randr to detect this and setup separate space on it
<alesguzik> but it does not enables second display automatically
<alesguzik> it does it after I enable it with xrandr
<alesguzik> So basically it's still my responsibility, not WM's
<ohsix> fantastic


# solution from https://bugs.freedesktop.org/show_bug.cgi?id=23705#c10 , despite it
# doesn't look like one is actually a way to go:
xrandr --fbmm `xrandr | sed -n '/ connected / {s/.* \([0-9]\+\)mm x \([0-9]\+\)mm/\1x\2/p;q}'`