X Error of failed request:  BadDrawable (invalid Pixmap or Window parameter)
Major opcode of failed request:  152 (DRI2)
Minor opcode of failed request:  8 (DRI2SwapBuffers     )
Resource id in failed request:  0x4200005
Serial number of failed request:  2166
Current serial number in output stream:  2167
primus: warning: timeout waiting for display worker
Segmentation fault (core dumped)

I don't get this on all OGL programs, but only particularly GPU intense ones. Also, I only get this using primusrun. optirun gives the same error no matter what I run:

[VGL] NOTICE: Pixel format of 2D X server does not match pixel format of
[VGL]    Pbuffer.  Disabling PBO readback.

I don't know what either of these mean. Neither of them stop the programs from running, but I'd like to fix the problem if there is one. Also, I prefer to use primusrun because it is faster and it does a better job with vertical sync, however, it only supports OGL 4.2. This isn't a big issue because the programs I write are forward compatible, but it still seems odd to me.

So basically I'd just like it if someone could explain to me what is happening and if there is something I can do about it. Thanks.