[FFmpeg-trac] #8790(build system:new): Compile NVDEC with Quadro RTX 6000 : "ERROR: failed checking for nvcc"

[FFmpeg]

#8790: Compile NVDEC with Quadro RTX 6000 : "ERROR: failed checking for nvcc"
-------------------------------------+-------------------------------------
             Reporter:  mliradelc    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  build        |                  Version:
  system                             |  unspecified
             Keywords:  configure,   |               Blocked By:
  nvidia, nvenc, nvcc, compile,      |
  build                              |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 == Summary of the bug: ==


 When you try to compile FFmpeg 4.3 - 4.3.1 with Nvidia options enabled,
 results in a Nvidia compiler error. during the configure phase.

 The details from the error log (config.log) are:
 {{{
 check_nvcc cuda_nvcc
 test_nvcc
 BEGIN /tmp/ffconf.lcEnfW9f/test.cu
     1   extern "C" {
     2       __global__ void hello(unsigned char *data) {}
     3   }
 END /tmp/ffconf.lcEnfW9f/test.cu
 nvcc -gencode arch= ,code=sm_30 -O2 -m64 -ptx -c -o
 /tmp/ffconf.lcEnfW9f/test.o /tmp/ffconf.lcEnfW9f/test.cu
 nvcc fatal   : Unsupported gpu architecture 'compute_30'
 ERROR: failed checking for nvcc.
 }}}


 ----

 == How to reproduce: ==

 Try to build ffmpeg, in my case using a self made script that you can find
 here[https://github.com/markus-perl/ffmpeg-build-script/blob/master/build-
 ffmpeg].




 ----


 == Why happens: ==


 This error happens because since the latest CUDA SDK (11.0) only accepts
 compute capability 5.2 - 8.0 (Maxwell, Pascal, Volta, Turing, Ampere).
 Compute_30


 == How to fix (Workaround): ==

 The fix is to modify the compute version from 30 to 52 in the configure
 file:
 {{{
 if enabled cuda_nvcc; then
     nvcc_default="nvcc"
     nvccflags_default="-gencode arch=compute_52,code=sm_52 -O2"
 else
     nvcc_default="clang"
     nvccflags_default="--cuda-gpu-arch=sm_52 -O2"
     NVCC_C=""
 fi

 }}}





 == System data ==
 Quadro RTX6000 card with the latest cuda sdk (11.0) and the nvidia drivers
 450.51.05.
 OS: Centos 7

 Nvidia SMI data:
 {{{
 +-----------------------------------------------------------------------------+
 | NVIDIA-SMI 450.51.05    Driver Version: 450.51.05    CUDA Version: 11.0
 |
 |-------------------------------+----------------------+----------------------+
 | GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr.
 ECC |
 | Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute
 M. |
 |                               |                      |               MIG
 M. |
 |===============================+======================+======================|
 |   0  Quadro RTX 6000     Off  | 00000000:3B:00.0 Off |
 0 |
 | N/A   31C    P0    23W / 250W |      0MiB / 22698MiB |      5%
 Default |
 |                               |                      |
 N/A |
 +-------------------------------+----------------------+----------------------+

 +-----------------------------------------------------------------------------+
 | Processes:
 |
 |  GPU   GI   CI        PID   Type   Process name                  GPU
 Memory |
 |        ID   ID                                                   Usage
 |
 |=============================================================================|
 |  No running processes found
 |
 +-----------------------------------------------------------------------------+

 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8790>
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