gr-fosphor install troubles:" Unable to share spectrum VBO into OpenCL context" openCL/GL sharing
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/oclSimp... [2] https://git.osmocom.org/gr-fosphor/tree/lib/fosphor/gl.c#n235
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@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/oclSimp...
[2] https://git.osmocom.org/gr-fosphor/tree/lib/fosphor/gl.c#n235
Hi Aaron, Finally got a chance to look at this in all details and : (1) indeed, removing that clear in deferred init fixes the issue (2) as you said, it's not even needed since the cl code will clear the buffers by itself. Looking at the code history, only the GL part had clear in the beginning and that wasn't enough in some cases and so later on I added CL clears and didn't remove the GL ones that had become redundant. Cheers, Sylvain
participants (2)
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Aaron Giles -
Sylvain Munaut