Hi,

I have a machine on which I'm completely unable to debug GUI programs. The machine runs Ubunutu 12.04 LTS.
If I try to debug, the whole system (at least X11, later the complete system) hangs as soon as there is a breakpoint in a GUI event handler.

It doesn't matter whether I do the debugging in Lazarus or in GDB directly.

The same program, the same breakpoint on another machine, same OS, works just fine.

The sole difference between the 2 machines is the graphics display: An NVidea card on the machine that is OK,
An on-board Intel chip on the machine that does not work.

So I'm inclined to suspect a buggy intel graphics driver.

Has anyone experienced such a situation? If so, I'd appreciate any hints you may have.

Michael.

I'm reminded of the Win-32 problems caused by HP printer drivers which failed to preserve the state of an FP control register.

Try debugging you app on a second instance of X ( display :1) in some cases X locks up when a breakpoint happens inside a X event.

Marc

Any hints on how to go about this ?

I see suggestions with references to xvnc etc; but how to set this up with Lazarus ?

Michael.

Il 14/07/2014 17:41, Michael Van Canneyt ha scritto:

Just some general guidelines, because each distro has its whims. What works with CentOs may fail with Ubuntu

1) Use:
Run -> Run Parameters -> Use launching application

2) Your launching application will be xinit, with a :1 parameter to specify a different display.

Sort of:
/usr/bin/xinit -e /path/to/executable [Command line parameters] -- :1

for further details, man xinit and man xterm (which in this setup is launched by xinit).

Hope that it helps,

Giuliano

Michael Van Canneyt wrote

Any hints on how to go about this ? I see suggestions with references to xvnc etc; but how to set this up with Lazarus ?

Use Xnest. That is how I used to debug the fpwm (Free Pascal Window Manager) project.

Example startup script...

--------[ start.sh ]----------------
#!/bin/bash
Xnest -ac :2 &
export DISPLAY=:2.0
./fpwm &
xterm &
------------[ end ]------------

Regards,
- Graeme -

..reminds me at a bug in intel Drivers i had trouble with on Linux-Mint cinnamon:

try this (quote from a forum
http://forums.linuxmint.com/viewtopic.php?f=221&t=146477 ):

*************************************************************

I have a Intel GPU, and i have these annoying black windows.

But you can do it this way:

create as root the file /etc/X11/xorg.conf

in terminal type ( if you don't have a /etc/X11/xorg.conf ) : sudo touch /etc/X11/xorg.conf

open editor in admin mode:
gksu gedit /etc/X11/xorg.conf

... and write/copy these lines:

Section "Device"
Identifier "Card0?
Driver "intel"
Option "AccelMethod" "sna"
EndSection

reboot

if that doesn't help do in terminal:
rm /etc/X11/xorg.conf
to delete it again

seems to work ok for me, but i have to test this some days first.

update: 10.07.14
..still working ok!
That was the solution for these annoying black pop-up windows!!

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