[PD] GEM + eee, segmentation fault

[Frank Barknecht]

Hallo,
Frank Barknecht hat gesagt: // Frank Barknecht wrote:

> IOhannes m zmoelnig hat gesagt: // IOhannes m zmoelnig wrote:
> 
> > hmm, this weekend i helped someone out to setup Gem on an intl gfx chip 
> > and lo and behold! it did not crash.
> > at least Gem claimed that it had "DRI enabled".
> 
> That's good news! I'll see if I can confirm this for my trusty Matrox
> machine, which isn't yet updated to the newest Gem.


Nope, still segfaults with a fresh cvs build:

$ gdb --args /usr/bin/pd -lib ./Gem

<make gemwin, destroy it, crash>

(gdb) bt
#0  0xb5481af0 in ?? ()
#1  0xb792bd1c in glXDestroyContext () from /usr/lib/libGL.so.1
#2  0xb792de40 in glXMakeCurrentReadSGI () from /usr/lib/libGL.so.1
#3  0xb792e0d3 in glXMakeCurrent () from /usr/lib/libGL.so.1
#4  0xb7b6f2d2 in gemWinMakeCurrent () from ./Gem.pd_linux
#5  0xb7b5e55a in GemMan::destroyWindow () from ./Gem.pd_linux
#6  0xb7b5f125 in GemMan::render () from ./Gem.pd_linux
#7  0x080b4803 in sched_tick (next_sys_time=86200320) at m_sched.c:372
#8  0x080b58d2 in m_mainloop () at m_sched.c:482
#9  0x080b8b2b in sys_main (argc=3, argv=0xbf8a5b54) at s_main.c:307
#10 0x080c1c8f in main (argc=Cannot access memory at address 0x0
) at s_entry.c:32


It behaves slightly different when using single context Gem. Here I
can destroy the gemwin once, but creating it again gives this
backtrace:

$ GEM_SINGLE_CONTEXT=1  gdb --args /usr/bin/pd -lib ./Gem

<make gemwin, destroy it, nocrash, "create, 1" gemwin again, crash>

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1210935616 (LWP 10999)]
0xb54d5cea in ?? ()
(gdb) bt
#0  0xb54d5cea in ?? ()
#1  0xb7938774 in __glXInitialize () from /usr/lib/libGL.so.1
#2  0xb79340ad in glXQueryVersion () from /usr/lib/libGL.so.1
#3  0xb7935dda in glXChooseVisual () from /usr/lib/libGL.so.1
#4  0xb7b7a75f in createGemWindow () from ./Gem.pd_linux
#5  0xb7b6af2c in GemMan::createWindow () from ./Gem.pd_linux
#6  0xb7b99dce in gemwin::createMess () from ./Gem.pd_linux
#7  0xb7b9a7a7 in gemwin::createMessCallback () from ./Gem.pd_linux
#8  0x080a93b4 in pd_typedmess (x=0x82db620, s=0x824e2a8, argc=0, argv=0xbfab036c) at m_class.c:730
#9  0x080ac047 in outlet_anything (x=0x82db6a8, s=0x824e2a8, argc=0, argv=0xbfab036c)
    at m_obj.c:390
#10 0x080a8fe2 in pd_typedmess (x=0x82db694, s=0x824e2a8, argc=0, argv=0xbfab036c) at m_class.c:749
#11 0x080adc0e in binbuf_eval (x=0x8237e90, target=Variable "target" is not available.
) at m_binbuf.c:722
#12 0x0805f8fd in message_click (x=0x82db678, xpos=188, ypos=137, shift=0, ctrl=0, alt=0)
    at g_text.c:303
#13 0x08063c21 in text_click (z=0x82db678, glist=0x823e360, xpix=188, ypix=137, shift=0, alt=0, 
    dbl=0, doit=1) at g_text.c:1073
#14 0x0808ac23 in canvas_doclick (x=0x823e360, xpos=188, ypos=137, which=1, mod=0, doit=1)
    at g_editor.c:92
#15 0x0808bc3b in canvas_mousedown (x=0x823e360, xpos=188, ypos=137, which=1, mod=0)
    at g_editor.c:1253
#16 0x080a9375 in pd_typedmess (x=0x823e360, s=0x822bc40, argc=4, argv=0xbfab06bc) at m_class.c:728
#17 0x080a8fe2 in pd_typedmess (x=0x82db4c0, s=0x822bc40, argc=4, argv=0xbfab06bc) at m_class.c:749
#18 0x080adc0e in binbuf_eval (x=0x82383d8, target=Variable "target" is not available.
) at m_binbuf.c:722
#19 0x080bbb65 in socketreceiver_read (x=0x8237ed8, fd=7) at s_inter.c:546
#20 0x080b8fd8 in sys_domicrosleep (microsec=Variable "microsec" is not available.
) at s_inter.c:184
#21 0x080ba007 in sys_pollgui () at s_inter.c:833
#22 0x080b5671 in m_mainloop () at m_sched.c:488
#23 0x080b8b2b in sys_main (argc=3, argv=0xbfab1f54) at s_main.c:307
#24 0x080c1c8f in main (argc=216, argv=0x82dcbf0) at s_entry.c:32

The second backtrace looks different from what I'm used to. I cannot really
read it: Is it a crash in Gem or in Pd? And what are the
(dis)advantages of running with single context?

This is on Debian stable with:
ii  libgl1-mesa-glx     6.5.1-0.5

pd MAIN from CVS, and a Matrox G450 (old but gold).

I will try the Intel laptop running Debian testing later.

Ciao
-- 
 Frank Barknecht                                     _ ______footils.org__