gr-fosphor install troubles:" Unable to share spectrum VBO into OpenCL context" openCL/GL sharing

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Sylvain Munaut 246tnt at gmail.com
Sat Sep 28 15:31:47 UTC 2019


Oh, wow, very interesting !

Thanks for taking the time to dig into this.

I just got a RTX2070, I still need to actually install some linux
version on it, but I'll be sure to confirm and merge a patch for that.

Cheers,

   Sylvain


On Sat, Sep 28, 2019 at 4:42 PM Aaron Giles <gilesam73 at gmail.com> wrote:
>
> >Yeah, the nVidia driver is annoying ... it used to work and they broke
> >it a few years ago and they don't care enough to fix it.
> >And since I got a new laptop a few years back, I don't have a nvidia
> >card to debug or work around it.
>
> I compared fosphor to the nVidia OpenCL Simple OpenGL Interop example [1] and noticed that fosphor calls glMapBuffer/glUnmapBuffer to clear the spectrum vbo between the calls to glBufferData and clCreateFromGLBuffer.  If I eliminate the map/memset/unmap here by removing  the call to gl_vbo_clear in gl_deferred_init [2], then clCreateFromGLBuffer returns CL_SUCCESS and fosphor appears to work with CL/GL sharing.  It is not clear to me if clearing the vbo_spectrum is necessary here, since cl_queue_clear_buffers later initializes the  mem_spectrum buffer to the noise floor.
>
> I'm using an nvidia GTX 1650 with version 430.50 of the nvidia drivers under Linux Mint 18.  A  friend of mine tested the GTX 1060 and also had  success with this workaround.
>
> Aaron
>
> [1]
> http://developer.download.nvidia.com/compute/DevZone/OpenCL/Projects/oclSimpleGL.tar.gz
>
> [2]
> https://git.osmocom.org/gr-fosphor/tree/lib/fosphor/gl.c#n235
>



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