[Dri-devel] remaining (reproducible) problems with 4.2.99.902 on Radeon M7

[Charl P. B. <c.p...@it...>]

Dear lists,

I have attached a slightly modified glthreads.c: I have modified it so that
selecting one of its windows and pressing any key will destroy the
associated glx context and subsequently that X window.

This destruction yields, in a very random fashion, one of the three
following symptoms on my Radeon M7 (7500 Mobility) laptop running
4.2.99.902:

1. The longstanding "radeon_vtxfmt.c:1057: radeonVtxfmtUnbindContext:
Assertion vb.context == ctx' failed." assertion error.

2. The infamous drmRadeonCmdBuffer: -22 and then program exit.  I am more
concerned about this symptom, because I'm seeing it with a real application
that I'm developing when destroying one of its multiple glx contexts.  This
is why I modified glthreads.c in the first place.

3. A good old segfault:
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1026 (LWP 712)]
0x404dd042 in _swrast_InvalidateState ()
   from /usr/X11R6/lib/modules/dri/radeon_dri.so
(gdb) bt
#0  0x404dd042 in _swrast_InvalidateState ()
   from /usr/X11R6/lib/modules/dri/radeon_dri.so
#1  0x4058b6ac in radeonInvalidateState ()
   from /usr/X11R6/lib/modules/dri/radeon_dri.so
#2  0x404a6edd in _mesa_update_state ()
   from /usr/X11R6/lib/modules/dri/radeon_dri.so
#3  0x4045e0e0 in _mesa_Clear () from /usr/X11R6/lib/modules/dri/radeon_dri.so
#4  0x401132f5 in _ts_Clear () from /usr/X11R6/lib/libGL.so.1
#5  0x08049275 in draw_loop ()
#6  0x0804995a in thread_function ()
#7  0x40337fa5 in pthread_start_thread () from /lib/libpthread.so.0
#8  0x40337fed in pthread_start_thread_event () from /lib/libpthread.so.0

4. X lockup: the mouse moves but can't interact with anything onscreen.  The
keyboard is dead.

If you keep on running glthreads with e.g. glthreads -n 3 and destroying a
single context, you should see each of these 4 symptoms at some or other
stage.  It would be wonderful if someone with deeper knowledge of the dark
Radeon driver interior could have a look at this.

Compile the attached code with:
gcc -I../include -O3 -ansi -pedantic -fPIC -ffast-math -D_SVID_SOURCE \
-D_BSD_SOURCE -DUSE_XSHM -DPTHREADS -I/usr/X11R6/include glthreads.c \
-L/usr/X11R6/lib -lglut -lGLU -lGL -lm -o glthreads

Thanks,
Charl

-- 
charl p. botha http://cpbotha.net/ http://visualisation.tudelft.nl/