Bug 884301 – dev-util/glslang update to 1.3.231 breaks vulkan in media-video/mpv

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Hadrien Lacour 2022-12-04 14:12:42 UTC]

Hello,

basically mpv's vulkan mode breaks with this update (reverting only glslang fixes it). Maybe a hairy problem, someone on IRC using mpv on Gentoo with same glslang and libplacebo (5.229.1, tried with git too) versions didn't have any problem.

The exact assertion is:
$ mpv --no-config --gpu-api=vulkan my.mkv
...
mpv: /var/tmp/portage/dev-util/glslang-1.3.231-r2/work/glslang-sdk-1.3.231.0/SPIRV/SpvBuilder.cpp:1075: spv::Id spv::Builder::createDebugGlobalVariable(spv::Id, const char*, spv::Id): Assertion `type != 0' failed.


https://github.com/mpv-player/mpv/issues/10965 for details

[Comment 1 Hadrien Lacour 2022-12-04 14:17:49 UTC]

Oh, and I tried with mainline mpv, to be sure the vapoursynth build option wasn't the culprit. Same problem.

emerge -pqv mpv:
[ebuild  N    ] media-video/mpv-0.35.0  USE="X alsa archive bluray cli drm iconv jpeg libmpv libplacebo lua opengl uchardet vapoursynth vulkan zlib (-aqua) -cdda (-coreaudio) -debug -dvb -dvd -egl -gamepad -jack -javascript -lcms -libcaca (-mmal) -nvenc -openal -pipewire -pulseaudio (-raspberry-pi) -rubberband -sdl (-selinux) -sndio -test -tools -vaapi -vdpau -wayland -xv -zimg" LUA_SINGLE_TARGET="luajit -lua5-1" PYTHON_SINGLE_TARGET="python3_10 -python3_9 -python3_11"

[Comment 2 Nick Sarnie 2022-12-04 18:38:18 UTC]

Just tired the repro steps and it works for me, so probably an upstream issue with specific mpv input. Will let the upstream bug figure it out.

[Comment 3 Hadrien Lacour 2022-12-04 18:55:24 UTC]

I see. Could it be hardware specific (with a codepath conditional on hardware)?

[Comment 4 Nick Sarnie 2022-12-04 18:56:54 UTC]

Sure, it could be that too. A developer for either glslang or mpv needs to investigate, it doesn't seem like a packaging issue.

[Comment 5 Ionen Wolkens 2022-12-04 19:02:58 UTC]

fwiw no issues either, same glslang-1.3.231 + libplacebo, built with exact same USE (minus vapoursynth), same mpv command and it works (using nvidia-drivers-525.60.1 fwiw)

with -v, shown being used too:
    [vo/gpu] Probing for best GPU context.
    [vo/gpu/vulkan] Initializing GPU context 'x11vk'
    [vo/gpu/libplacebo] Initialized libplacebo v5.229.0 (API v229)

emerge --info? sometime even different optimizations could trigger these issues

[Comment 6 Ionen Wolkens 2022-12-04 19:29:03 UTC]

The new assert non-trivially comes from https://github.com/KhronosGroup/glslang/pull/2985, not that I can say what's up with it and why it's failing for you (as sarnex says, that looks more for upstream).

[Comment 7 Hadrien Lacour 2022-12-04 19:46:21 UTC]

Created attachment 840103 [details]
emerge --info

I use -O3 -march=native and stable mesa with a RX580. Nothing out-of-the-ordinary for a Gentoo user, I'd say.

[Comment 8 Nick Sarnie 2022-12-04 20:17:27 UTC]

If you want to try stuff, maybe
1) Try dropping to -O2 for glslang/mpv, which is what I'm using
2) Try unstable mesa, which is what I'm using

[Comment 9 Hadrien Lacour 2022-12-04 20:34:42 UTC]

No luck. Guess I'll just wait for upstream to inspect my gdb backtrace.

[Comment 10 Nick Sarnie 2022-12-04 20:35:52 UTC]

Just to be complete, you could also try O2 for libplacebo and shaderc since those are involved in the backtrace. But just a hail mary.

[Comment 11 Hadrien Lacour 2022-12-04 22:09:29 UTC]

So:
* According to upstream, I tried rebuilding media-libs/shaderc, but hit https://bugs.gentoo.org/show_bug.cgi?id=884379
* After unmasking everything that needed to in that unholy dependency mess, problem is fixed.

I don't know if something is breaking ABI contract or anything, sadly.

[Comment 12 Nick Sarnie 2022-12-04 22:12:46 UTC]

I think I see the problem. If you have irc can you join #gentoo-desktop and ping me (sarnex)