nv04_stateError message when attempting to run EMC

Hi- I get the following Debug message when attempting to run EMC:-
"python: nv04_state_raster.c:126: get_blend_func: Assertion `0' failed."
Can anyone de-mystify me as to what it might mean?
Thanks

It would help if you told us what operating system your running and what version of LinuxCNC or EMC your running as well as when you get the error. Also zip your config files and attach them.

JT

Hi- I am using the iso I downloaded a couple of weeks ago.
Debian Wheezy Version 7 I think, and LinuxCNC 2.6.1. I am running this on an old home brew PC with an AMD Sempron 1.6G processor, so I dont know if this is causing any problems. However the stepper config wizard appears to run successfully.
Attached is the config folder contents.
Jeff

Treetop wrote: Can anyone de-mystify me as to what it might mean?

Googling the file name (nv04_state_raster.c) suggests that the offending code is part of the "nouveau" graphics drivers.

Googling the exact error message brought up a similar thread on the Russian CNC club forum:
translate.google.com/translate?hl=en&sl=...3D145308&prev=search

It seems to be something that can be avoided by using software open-gl.
wiki.linuxcnc.org/cgi-bin/wiki.pl?Troubl...oftware_based_OpenGL

Andy- many many thanks for pointing me in the right direction.
Disabling nouveau DID clear the problem, albeit with poor quality graphics.
It seems the nvidia driver specific to my GPU is not compatible with Debian Wheezy, so that was not an option.
It looked to me as if the Open GL solution suggested on the wiki used the CPU to do all the rendering rather than the GPU so I thought that might challenge my low spec processor in this real time application.
Anyway, I had a spare graphics card with less ancient technology, and plugging that in has restored the graphics and LinusCNC runs without issue.

Thanks again.
Jeff

I looked into this. I found a copy of " nv04_state_raster.c " online and looked at the function get_blend_func. If an unknown value is encountered in this function, it causes the fatal error you encountered.

AXIS (and Gremlin and other previewing user interfaces) use several blend modes defined in OpenGL. One of them is GL_CONSTANT_ALPHA (you can see it listed in the OpenGL SDK documentation ), but this is not one of the options supported by get_blend_func.

In my opinion, this is a bug in the OpenGL driver that LinuxCNC just happens to hit consistently. You can try filing a bug with your distro or with the upstream library (mesa). I suspect that you can reproduce the problem by taking any old OpenGL demo such as glxgears and adding a call to glBlendFunc(GL_ONE, GL_CONSTANT_ALPHA) and glEnable(GL_BLEND).

I don't have an affected graphics card handy so I can't do this myself.