VOGONS


First post, by CJEC

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Apologies if this has been addressed before. I did search the forums, but didn't find anything, and I wanted to get this posted before I head off to work.

I'm using DOSBox 0.74 for Linux, installed from repositories.

My host system is running Linux Mint 17 KDE version (KDE version 4.13.3). I have dual monitors, and normally run a single desktop spanning the two monitors.

$ lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GT218 [GeForce 210] (rev a2)
$ xrandr | grep connect
DVI-I-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
HDMI-1 disconnected (normal left inverted right x axis y axis)
VGA-1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 477mm x 268mm

KDE System Settings > Display Configuration has the DVI-I-1 to the left of the VGA-1.

The following is reproducible:

1. Launch DOSBox in windowed mode.
2. Press Alt-Enter to switch to full screen. At this point I get a fullscreen DOSBox mirrored to both monitors.
3. Press Alt-Enter to switch back to windowed mode.

My system is still in mirrored mode, with one desktop mirrored on both monitors. System Settings > Display Configuration now shows only the VGA-1 monitor. xrandr still reports the three monitors as above.

This:

xrandr --output VGA-1 --mode 1920x1080 --pos 1920x0 --output DVI-I-1 --mode 1920x1080 --pos 0x0

puts me back to where I want to be (until the next time I run DOSBox fullscreen), and the HDMI now shows up in Display Configuration again.

Looks like a DOSBox bug, but what do I know?

Reply 1 of 6, by truth_deleted

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Test by compiling your own version rather than trusting a repository. Also, you may try a win32 version in wine if you are not familiar with compiling software with libraries.

Gog.com supports DOS games on linux, an especially good option for those who are too busy or unable to troubleshoot linux systems. However, I am not aware of DOS games which require multiple monitors to run properly.

Reply 2 of 6, by Dominus

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It's a problem with SDL of which the SDL guys are aware but won't do anything to fix... Dual monitor setups are not their big thing... Nor is SDL 1.2x which they don't want to actively develop anymore

Windows 3.1x guide for DOSBox
60 seconds guide to DOSBox
DOSBox SVN snapshot for macOS (10.4-11.x ppc/intel 32/64bit) notarized for gatekeeper

Reply 3 of 6, by CJEC

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If someone wants to walk me through the compilation steps -- I'm not a developer -- I'll give that a try. Meanwhile I downloaded the latest Win32 version from Sourceforge and installed it under Wine. The Win32 version never touches the secondary display. Fullscreen appears only on my primary display, and switching back to windowed mode leaves me with my original setup.

(However, the switch back to windowed mode leaves the contents of the DOSBox window black; can't see anything. But that's an issue for another day.)

It occurs to me I should have included the contents of dosbox.conf.

[sdl]
fullscreen=false
fulldouble=false
fullresolution=original
#windowresolution=original
windowresolution=1024x768
output=opengl
autolock=true
sensitivity=100
waitonerror=true
priority=higher,normal
mapperfile=mapper-0.74.map
usescancodes=true

[dosbox]
language=
machine=svga_s3
captures=capture
memsize=16

[render]
frameskip=0
aspect=false
scaler=normal2x

Reply 5 of 6, by CJEC

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Thanks, Dominus. I'll give that a try, but I only tried it because truth5678 suggested it.

Speaking of which, I'm unclear what the test is intended to show -- that the bug doesn't exist in the Windows version, or only that Wine doesn't expose my dual monitors to DOSBox?

When I get home I'll also try playing around with other outputs to see if that gets around the original problem (which, sounds like it'll never be getting fixed).

BTW, I'm not trying to run DOSBox in dual monitor mode; I'd just be happy if DOSBox left my settings alone.

Reply 6 of 6, by truth_deleted

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Does dosbox (linux version) work in windowed mode? If so, is this just a full screen issue where running multiple monitors(*)? Have you set scaler=none where running all tests?

SDL1 applications (like dosbox) do not support a multiple monitor setup in linux. My guess is that SDL1 is receiving the screen resolution from its X11 driver and that resolution is the total across both monitors. I also assume that you exported the SDL parameter "SDL_VIDEO_FULLSCREEN_DISPLAY=0", although that is not certain to confine the dosbox fullscreen window to a single monitor. In any case, SDL2 should detect the screen resolution for each of the different monitors (there is a SDL2 patch in development) and avoid the issue.

Here's another SDL (SDL1) patch to test: http://blog.pdark.de/2011/12/04/forcing-sdl-t … in-window-size/.

Apparently, wine is multi-monitor aware. If another output mode fixes the other issue where running dosbox in wine, then that is another option.

* http://trac.wildfiregames.com/ticket/1916?cve … n=0&cnum_hist=5