[directfb-users] DirectFB application silently crashes when event buffer is used

[Jan Jakubuv]

Hi,

I'm experiencing the following problem when using DirectFB 1.2.8 on an
embedded linux device running kernel 2.6.38 (mipsel). The device is
equipped with a tslib-compatible touchscreen. It works fine with
DirectFB and I can see the mouse cursor on the screen and it moves
correctly when the screen is touched.

However, when I create an event buffer to process window events, the
application suddenly crashes when a screen is touched. This happens
independently on whether or not I was trying to process events from
the buffer. The weird thing is how it crashes: it simply terminates,
leaving no error message, no core dump, simply nothing. I've tried
some debug outputs and it seems that the application terminates at
random positions whenever a screen is touched (sometimes it can be
touched few times but it always crashes later on).

Also I've made the following observation. My application also uses a
serial connection (using libmodbus) and when I disable this serial
line (i.e. not open it) then everything works fine as expected. I've
tried to separate DirectFB and serial line communication into
different threads and even processes but it did not help.

Does anyone have an idea what might be wrong. I would be grateful for
any suggestion as I'm becoming a little bit desperate ;-)

Thanks,

Jan

[Jan Jakubuv]

Hi,

the problem is SOLVED, sorry for bothering you. It was not a problem
with DirectFB but the thing was that the modbus connection got
incidentally closed and I was still using the closed modbus context
(handle) to communicate over it. Somehow this made the app crash only
when a DirectFB event buffer was used and for some reasons (unknown to
me) it usually crashed in DrawString method.

Anyway, thanks for your time.

Jan

Post by Jan Jakubuv
Hi,
I'm experiencing the following problem when using DirectFB 1.2.8 on an
embedded linux device running kernel 2.6.38 (mipsel). The device is
equipped with a tslib-compatible touchscreen. It works fine with
DirectFB and I can see the mouse cursor on the screen and it moves
correctly when the screen is touched.
However, when I create an event buffer to process window events, the
application suddenly crashes when a screen is touched. This happens
independently on whether or not I was trying to process events from
the buffer. The weird thing is how it crashes: it simply terminates,
leaving no error message, no core dump, simply nothing. I've tried
some debug outputs and it seems that the application terminates at
random positions whenever a screen is touched (sometimes it can be
touched few times but it always crashes later on).
Also I've made the following observation. My application also uses a
serial connection (using libmodbus) and when I disable this serial
line (i.e. not open it) then everything works fine as expected. I've
tried to separate DirectFB and serial line communication into
different threads and even processes but it did not help.
Does anyone have an idea what might be wrong. I would be grateful for
any suggestion as I'm becoming a little bit desperate ;-)
Thanks,
Jan