Heya All, I have some OpenGL code that used to work fine on Jessie, but now I'm running Stretch I can't seem to get a context above 1.3. I have a ThinkPad X220, with cpuinfo reporting that it has an "Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz".
This I think is the relevant bit of code, but I'm happy to provide the rest,
it's just noddy glued together examples to make a cube spin:
window = SDL_CreateWindow("SDL", SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, 0, 0,
SDL_WINDOW_FULLSCREEN_DESKTOP
| SDL_WINDOW_OPENGL);
if (!window) sdl_fail();
if (SDL_ShowCursor(SDL_DISABLE) < 0) sdl_fail();
/* initialise opengl */
if (SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2) != 0) sdl_fail
if (SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1) != 0) sdl_fail
if (SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1) != 0) sdl_fail();
if (!SDL_GL_CreateContext(window)) sdl_fail();
glEnable(GL_DEPTH_TEST);
{
GLenum err = glewInit();
if (GLEW_OK != err) {
fprintf(stderr, "Error: %s\n", glewGetErrorString(err));
exit(1);
}
}
printf("GL_RENDERER:\t%s\n", glGetString(GL_RENDERER));
printf("GL_VERSION:\t%s\n", glGetString(GL_VERSION));
printf("GL_VENDOR:\t%s\n", glGetString(GL_VENDOR));
Just running as it is, I get this output:
$ ./glthing
MESA-LOADER: failed to retrieve device information
GL_RENDERER: Mesa DRI Unknown Intel Chipset
GL_VERSION: 1.3 Mesa 13.0.6
GL_VENDOR: Intel Open Source Technology Center
Segmentation fault
The segfault is happening just below this code, when it tries to call
glBindBuffers (which isn't in OpenGL 1.3). If I request an OpenGL 3.0 context
(I think this cpu should support slightly above that) it fails when creating the
context:
$ ./glthing
MESA-LOADER: failed to retrieve device information
Could not create GL context: GLXBadFBConfig
If I dont use GLEW, and just use the OpenGL headers directly (and remove
anything not OpenGL 1) then I get the higher context, this seems to match what
happens with glxgears (which from the code seems to use the immediate mode):
$ glxgears -info 2>&1 | grep GL_ | head -n 3
GL_RENDERER = Mesa DRI Intel(R) Sandybridge Mobile
GL_VERSION = 3.0 Mesa 13.0.6
GL_VENDOR = Intel Open Source Technology Center
There's no mention of the MESA-LOADER line in the raw output of glxgears. Some
searching online doesn't seem to have gotten me anything useful about what that
might be caused by.
Supertuxkart reports that same GLXBadFBConfig line, and then seems to work
anyway (reporting a 3.0 context).
$ supertuxkart --log=2 | sed -ne '/Irrlicht/,$p'
Irrlicht Engine version 1.8.0
Linux 4.9.0-6-amd64 #1 SMP Debian 4.9.82-1+deb9u3 (2018-03-02) x86_64
[warn ] [IrrDriver Temp Logger]: Level 2: X Error: GLXBadFBConfig
[warn ] [IrrDriver Temp Logger]: Level 2: From call : unknown
[warn ] [IrrDriver Temp Logger]: Level 3: Vertex shader compilation
failed at position -1:
[warn ] [IrrDriver Temp Logger]: Level 3: Pixel shader compilation failed
at position -1:
[warn ] [IrrDriver Temp Logger]: Level 3: Vertex shader compilation
failed at position -1:
[warn ] [IrrDriver Temp Logger]: Level 3: Pixel shader compilation failed
at position -1:
[warn ] [IrrDriver Temp Logger]: Level 3: Vertex shader compilation
failed at position -1:
[warn ] [IrrDriver Temp Logger]: Level 3: Pixel shader compilation failed
at position -1:
[info ] IrrDriver: OpenGL version: 3.3
[info ] IrrDriver: OpenGL vendor: Intel Open Source Technology Center
[info ] IrrDriver: OpenGL renderer: Mesa DRI Intel(R) Sandybridge Mobile
[info ] IrrDriver: OpenGL version string: 3.3 (Core Profile) Mesa 13.0.6
I don't have any Xorg.conf.d lines now, although I've tried the intel and
modesetting driver, and both sna and uxa.
Oh, also if I use the LIBGL_SOFTWARE_ALWAYS=true environment variable the code
runs perfetly fine:
$ LIBGL_ALWAYS_SOFTWARE=true ./glthing
GL_VERSION: Gallium 0.4 on llvmpipe (LLVM 3.9, 256 bits)
GL_VERSION: 3.0 Mesa 13.0.6
GL_VERSION: VMware, Inc.
For the complexity of things that I'm rendering right now, software is perfectly
fine... it'd just be nice to have some idea of what's going on. Any chance
anyone could shed some light on this for me?
--
Daniel Keast
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