Bug in build options of Xephyr

Dinithion · 08-22-2014, 01:07 PM

Could anyone tell me which build options are used when the slackware team is compiling the xorg-server-xephyr package?

There is a bug in slackware where Xephyr is built without evdev support, which makes no sense since slackware uses it.

I need to recompile this package so that I can enable evdev and also apply a patch to fix a Xephyr bug.

Short story:
I have gotten evdev support to work in Xephyr simply by running
./autogen.sh --disable-xorg --enable-xephyr --enable-kdrive-evdev --prefix=/usr

However, I'm not building it with the same build options as that of the rest of Xorg, thus there are some bugs present. Most notably, if I unplug my mouse, the keyboard will stop working and the CPU load will go to 100%.

Longer story:
I'm working on transforming my laptop into a multiseat computer. As of now I only have a laptop with a VGA/DVI output and I don't have the economy to do anything about it either.

So the multiseat works like this:

Start an X server with two screens
Start one Xephyr display for each screen and attach one keyboard and one mouse to each Xephyr session.
Configure kdm start one session for each Xephyr display.

SUCCESS!! Almost!

Xephyr has a bug where if you unplug a mouse/keyboard it will stop using the evdev device, even though you plug it back in. There is a patch to fix it, but it is not working properly. The patch is for an older version of Xorg than what slackware uses, so I had to add it manually. The patch works for the mouse but not for the keyboard, even though the code is more or less identical.

The symptom is that when you unplug the mouse and replug it, the mouse will work but not the keyboard, which was never unplugged, and the CPU load goes to 100%. (If you unplug the keyboard and re-plug it you don't get that behavior)

I get the same CPU behavior when I compile without the patch, (but with evdev) which leads me to believe that there is something wrong with my build of Xephyr and not the patch it self. Since my c-skills are really limited, I figured it would be easier to test it with the correct build-options for Xephyr.

Edit:
Just a final note, this is a problem because my mouse occasionally glitches and drop the USB-connection for whatever reason. I could technically get a new mouse though, but I like this one.

Didier Spaier · 08-23-2014, 06:52 AM

Quote:

Originally Posted by Dinithion

Could anyone tell me which build options are used when the slackware team is compiling the xorg-server-xephyr package?

See /source/x/x11/configure/xorg-server.

Quote:

There is a bug in slackware where Xephyr is built without evdev support [...]

No. In aforementioned script I see:

Code:

# Servers to build:
BUILD_SERVERS="--enable-xorg \
  --enable-dmx \
  --enable-xvfb \
  --enable-xnest \
  --enable-kdrive \
  --enable-xephyr \
  --enable-xfbdev \
  --enable-config-udev \
  --disable-config-hal"

On top of that, the main SlackBuild is /source/x/x11/x11.SlackBuild.

Dinithion · 08-23-2014, 08:33 AM

Woah! I didn't realize the slackbuilds got shipped with the iso! Thank you!

I wouldn't know about those settings, but if you start a Xephyr session and try to bind a keyboard, you will see that it reports an evdev related error and the keyboard/mouse is not working. When Xephyr is recompiled with --enable-kdrive-evdev keyboard/mouse binding is working.

Anyway, thank you for helping with the build flags. I will report back when I've tried it for future reference.