I just setup the latest 4.1.1 maemo SDK on Ubuntu 8.10, and Xephyr doesn't seem to want to run -

Xephyr :2 -host-cursor -screen 800x480x16 -dpi 96 -ac -extension Composite
*** glibc detected *** Xephyr: double free or corruption (!prev): 0x0981a3c0 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6[0xb7c0e3f4]
/lib/tls/i686/cmov/libc.so.6(cfree+0x96)[0xb7c10456]
Xephyr(Xfree+0x21)[0x81d7cf1]
Xephyr[0x80bcc52]
...

Any thoughts on what's wrong or a workaround?

So, any thoughts ? I have exactly the same problem... Could someone help me please !?

I didn't meet such problem on my installation of Ubuntu 8.10. Only I can suggest is to use another nested X server, for example, xnest (it is available in Ubuntu repository).

Perhaps start removing Xephyr parameters, see if you can run Xephyr with just ":2 -screen 800x480x16"

Hello !

Thanks for hints ! In this case which was after all simple, I installed the right driver for ATI controller and that was it. To the next challenges...

Ok, Xnest gets me further, with the following (in case anyone else runs into this) -

Xnest :2 -ac -geometry 800x480 -dpi 96 -extension Composite

but now I seem to have a keyboard issue...

maemo-launcher: invoking '/usr/bin/hildon-input-method.launch'
/home/jbyrne/.osso/current-gtk-key-theme:1: Unable to find include file: "keybindings.rc"
Starting Hildon Desktop
maemo-launcher: invoking '/usr/bin/hildon-desktop.launch'
hildon-input-method[7896]: GLIB MESSAGE default - ui up and running
/home/jbyrne/.osso/current-gtk-key-theme:1: Unable to find include file: "keybindings.rc"
[sbox-DIABLO_X86: ~] > hildon-desktop[7910]: GLIB DEBUG default - mission_control_get_presence_actual: MC not running.
Audio File Library: could not open file '/usr/share/sounds/ui-window_open.wav' [error 3]
Audio File Library: could not open file '/usr/share/sounds/ui-window_close.wav' [error 3]

so I got rid of the 'include' in ~/.osso/current-gtk-key-theme and that quiets the keybindings.rc nag, but another hildon-desktop X-related error keeps things from starting up...

af-sb-init.sh start
Note: For remote X connections DISPLAY should contain hostname!
Sample files present.
DBUS system bus is already running, doing nothing
D-BUS session bus daemon is already running, doing nothing
Starting Maemo Launcher: maemo-launcher start failed.
Sapwood image server is already running, doing nothing
Matchbox window manager is already running, doing nothing
clipboard-manager is already running, doing nothing
Keyboard is already running, doing nothing
Starting Hildon Desktop
maemo-launcher: invoking '/usr/bin/hildon-desktop.launch'
[sbox-DIABLO_X86: ~/.osso] > hildon-desktop[8075]: GLIB DEBUG default - mission_control_get_presence_actual: MC not running.
Audio File Library: could not open file '/usr/share/sounds/ui-window_open.wav' [error 3]
Audio File Library: could not open file '/usr/share/sounds/ui-window_close.wav' [error 3]
The program 'hildon-desktop' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadValue (integer parameter out of range for operation)'.
(Details: serial 376 error_code 2 request_code 53 minor_code 0)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)
maemo-launcher: child (pid=8075) terminated due to exit()=1

Edit: BTW, I considered updating my ATI driver as timosk did, but I have a Radeon 7550 AGP card that's too old for the propietary ATI offerings. I actually bought a Radeon 9250 AGP card a few months ago, but it was completely unusable (screen flickering between complete blackness and desktop , and the Radeon 7550 has always been a great card with the community Xfree86 and X.org drivers, decent 3D acceleration, etc...

I've been a Slackware user for many years, and only installed Ubuntu to make the maemo/scratchbox setup much easier.

I might try an Ubuntu install in VMware, and see if that helps abstract the X-related errors away.

I had the same issue with Jaunty (I know, I know... bleeding edge) and I got it to run with:

Xephyr :2 -host-cursor

I also have ATi (mobile Radeon) and am using whatever driver was detected and configured by the installer. Wonder if that's my issue too?!

Thanks, that did the trick -- Xephyr with minimal options.

Xephyr :2 -host-cursor -ac

and then

af-sb-init.sh start

in scratchbox.

I noticed when I tried running the Jaunty version of Xephyr on the tablet that giving it too many parameters causes problems. For instance, using the -parent and -screen parameters causes it to act bizarrely. It seems that the -screen parameter is no longer required?

I ran into this too; for some reason the xephyr build in 8.10 is profoundly unhappy running at 16 bits on my 24-bit X server. (Any other bit depth runs fine!) I run it at 24 bits instead:

Seems to work just as well. I'd be wary if I was doing anything goofy with color in my app, though.