Problem replaying trace on Mesa 10.1.4

[Alexander Monakov]

On Tue, 27 May 2014, io.github.apitrace at io7m.com wrote:

> 1 1930 glXCreateContextAttribsARB(dpy = 0x7f8a4400b040,
> config = 0x7f8a44043de0, share_context = NULL, direct = True,
> attrib_list = {GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
>                GLX_CONTEXT_MINOR_VERSION_ARB, 4,
>                GLX_RENDER_TYPE, 0x8014, GLX_CONTEXT_FLAGS_ARB, 0x0,
>                GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
>                0}) = NULL

The above asks for a 4.4 core context that is not supported by your underlying
OpenGL implementation.  The extension specification says:

      * If <config> does not support compatible OpenGL contexts
        providing the requested API major and minor version,
        forward-compatible flag, and debug context flag, GLXBadFBConfig
        is generated.

So as I understand generating GLXBadFBConfig error is expected and it's the
fact that it was working before that should be surprising, not that it's
properly rejected now.

Actually... looking at the trace I see that the application was trying 4.4,
4.3, etc. until eventually succeeding with 3.3.  Apitrace dies because X
protocol errors are by default fatal, and I don't see an XSetErrorHandler call
anywhere.  It probably should be fixed.

I don't know why you weren't seeing this problem before; it looks like Xorg or
Mesa started correctly delivering GLXBadFBConfig, but I don't know when that
changed.  It would be nice if any Mesa/Xorg developers reading the list could
comment.

Hope that helps,
Alexander