[SDL] SDL tampers with display power settings on the sly

Erik esigra at gmail.com
Fri Feb 22 19:22:20 PST 2008

SDL tampers with the power management settings of my display on the sly. 
After running an SDL program, the display never turns off. It should turn
off after a minute of inactivity. I have to go to 
kcontrol->peripherals->display->powersave, change something, change it 
back and press Apply. Then the power management is restored.

So I have to keep a kcontrol instance open all the time and do that 
after running an SDL program. This is annoying, but it was much worse 
before I knew
that it was SDL programs that caused it.

To reproduce:
1. Wait a minute until the display turns off, to check that the power 
management is working properly.
2. Build and run any SDL program, such as the attached testcase (gcc 
-Wall -Wextra -I/usr/include/SDL prov.c -lSDL -o prov&&./prov).
3. Wait a minute to see that the power management has stopped working.
4. Switch to kcontrol->peripherals->display->powersave, change some 
setting, change it back and press Apply.
5. Wait a minute to see that the power management works again.

The power management stops working when the SDL program is started and 
remains dysfunctional even after the SDL-program has been closed.

Some system information:
* Dell INSPIRON | 8600 (laptop)
* VGA compatible controller: ATI Technologies Inc RV350 [Mobility Radeon 
9600 M10]
* Linux 2.6.23-gentoo-r8 Intel(R) Pentium(R) M processor 1.60GHz
* [ebuild   R   ] x11-base/xorg-server-  USE="dri ipv6 nptl 
sdl xorg -3dfx -debug -dmx -kdrive -minimal -xprint" 
INPUT_DEVICES="keyboard mouse -acecad -aiptek -calcomp -citron 
-digitaledge -dmc -dynapro -elo2300 -elographics -evdev -fpit -hyperpen 
-jamstudio -joystick -magellan -microtouch -mutouch -palmax -penmount 
-spaceorb -summa -synaptics -tek4957 -ur98 -vmmouse -void -wacom" 
VIDEO_CARDS="radeon -apm -ark -chips -cirrus -cyrix -dummy -epson -fbdev 
-fglrx -glint -i128 -i740 -i810 (-impact) -imstt -mach64 -mga -neomagic 
(-newport) -nsc -nv -nvidia -r128 -rendition -s3 -s3virge -savage 
-siliconmotion -sis -sisusb (-sunbw2) (-suncg14) (-suncg3) (-suncg6) 
(-sunffb) (-sunleo) (-suntcx) -tdfx -tga -trident -tseng -v4l -vesa -vga 
-via -vmware -voodoo" 0 kB
* [ebuild   R   ] media-libs/libsdl-1.2.11-r2  USE="X alsa arts dga 
directfb fbcon ggi opengl xinerama xv -aalib -custom-cflags -esd 
-libcaca -nas -noaudio -nojoystick -novideo -oss -svga" 0 kB
* [ebuild   R   ] kde-base/kcontrol-3.5.8-r2  USE="arts kdeenablefinal 
kdehiddenvisibility opengl xinerama -debug -ieee1394 -joystick 
-logitech-mouse" 0 kB
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