Xgl/Xglx: initialize_visual_and_buffer: Assertion `v->BitsPerPixel > 0' failed.

[Brian Paul]

Ben Skeggs wrote:
> Am Freitag, den 06.01.2006, 11:12 -0700 schrieb Brian Paul:
> 
>>Christopher Bayliss wrote:
>>
>>>Christian Parpart wrote:
>>>
>>>
>>>>Hi all,
>>>>
>>>>after having finally(!) compiled and installed the xserver from very recent 
>>>>CVS state, I were curious on Xgl/Xglx but when invoking them I get the 
>>>>following:
>>>>
>>>>trapni at battousai /opt/sandbox/fdo/bin $ ./Xgl :1
>>>>Xgl: /home/trapni/src/Xorg/xserver/../Mesa//src/mesa/drivers/x11/xm_api.c:1223: 
>>>>initialize_visual_and_buffer: Assertion `v->BitsPerPixel > 0' failed.
>>>>Aborted
>>>>
>>>>trapni at battousai /opt/sandbox/fdo/bin $ ./Xglx :1 -ac -screen 800x600
>>>>Xglx: /home/trapni/src/Xorg/xserver/../Mesa//src/mesa/drivers/x11/xm_api.c:1223: 
>>>>initialize_visual_and_buffer: Assertion `v->BitsPerPixel > 0' failed.
>>>>Aborted
>>>>
>>>>I ran this within my current X session.
>>>>Any idea on why this is happening?
>>>
>>>
>>>I don't know what's happening but I had the same problem. Xgl appears to
>>>work just fine if you comment the line out and recompile. It appears to
>>>be a check on the requested colour depth of the output screen.
>>>Alternatively, could try defining a colour depth when calling Xgl.
>>
>>Could someone provide a stack trace?
> 
> 
> I see the same problem here. AMD64, Xgl build from xserver cvs. 

This might be a symptom of a bug else where in the server code.  I'm 
adding a few new assertions to the Mesa code.  Can you grab the latest 
from CVS and try again?

Here's the patch:

diff -r1.97 xm_api.c
255a256
 >    assert(depth > 0);
1565a1567
 >    assert(visinfo->nplanes > 0);


In the stack trace, like 985 of xf86glx.c doesn't correspond to 
__MESA_screenProbe().  At least not in the xc or xserver CVS trees 
that I'm looking at:

 > #5  0x00002aaaac3d4880 in __MESA_screenProbe (screen=0) at 
xf86glx.c:985
 > #6  0x00002aaaac723708 in xglScreenProbe (screen=16526) at
 > xglglxext.c:5032
 > #7  0x00002aaaac267982 in __glXScreenInit (numscreens=1) at
 > glxscreens.c:357
 > #8  0x00000000004a273d in InitExtensions (argc=<value optimized out>,
 > argv=<value optimized out>)
 >     at miinitext.c:346
 > #9  0x000000000043c37e in main (argc=3, argv=0x7fffffc60eb8, 
envp=<value
 > optimized out>)
 >     at main.c:364


I see the call to XMesaCreateVisual() at line 1447.  It would be 
helpful to put this assertion there:

assert(pVis->nplanes > 0);

-Brian