Commit 6a5b5095 authored by OPNA2608's avatar OPNA2608
Browse files

ffmpeg: Fix CPU-related settings on POWER 

The defaults with the `generic` CPU target are somewhere between the ppc64 and ppc64le baseline.
More specific CPU targets don't have perfect settings either.

Just try to configure together a set of baseline-compatible settings.
parent 722ba864

pkgs/development/libraries/ffmpeg/generic.nix

+19 −0
Original line number Diff line number Diff line
@@ -795,6 +795,25 @@ stdenv.mkDerivation ( 
      (enableFeature withExtraWarnings "extra-warnings")

      (enableFeature withStripping "stripping")

    ]

    ++ optionals (stdenv.hostPlatform.isPower) [

      # FFmpeg expects us to pass `--cpu=` to pick a specific feature set to compile for. If unset, it defaults to `generic`.

      # For POWER, the default doesn't produce baseline-compliant settings. Passing a baseline-like CPU as a target doesn't

      # produce entirely correct settings either - POWER4 leaves AltiVec enabled, but that's only guaranteed with POWER6.

      # Just configure together everything on our own.



      # Easy: Only ppc64le's baseline is recent enough to guarantee all of these.

      (enableFeature (stdenv.hostPlatform.isPower64 && stdenv.hostPlatform.isLittleEndian) "altivec")

      (enableFeature (stdenv.hostPlatform.isPower64 && stdenv.hostPlatform.isLittleEndian) "vsx")

      (enableFeature (stdenv.hostPlatform.isPower64 && stdenv.hostPlatform.isLittleEndian) "power8")

      (enableFeature (stdenv.hostPlatform.isPower64 && stdenv.hostPlatform.isLittleEndian) "ldbrx")



      # Instructions that are highly specific to that series of 32-bit embedded CPUs. Never try to enable them.

      (enableFeature false "ppc4xx")



      # I *think* enabling this on 64-bit POWER is correct? Struggling to find much info on when/where this was introduced.

      # Definitely present on the Apple G5, and likely Freescale e5500/e6500 as well.

      (enableFeature (stdenv.hostPlatform.isPower64) "dcbzl")

    ]

    ++ optionals (stdenv.hostPlatform != stdenv.buildPlatform) [

      "--cross-prefix=${stdenv.cc.targetPrefix}"

      "--enable-cross-compile"