What was your last RTFM adventure?

What was your last RTFM adventure? Tinker this, read that, make something smoother! Or explodier.

As for me, I wanted to see how many videos I could run at once. (Answer: 60 frames per second or 60 frames per second?)

With my sights on GPUizing some ethically sourced motion pictures, I RTFW, graphed, and slapped on environment variables and flags like Lego bricks. I got the Intel VAAPI thingamabob to jaunt by (and found that it butterized my mpv videos)

$ pacman -S blahblahblahblahblahtfm
$ mpv --show-profile=fast
Profile fast: 
 scale=bilinear
 dscale=bilinear
 dither=no
 correct-downscaling=no
 linear-downscaling=no
 sigmoid-upscaling=no
 hdr-compute-peak=no
 allow-delayed-peak-detect=yes
$ mpv --hwdec=auto --profile=fast graphwar-god-4KEDIT.mp4
# fucking silk

But there was no pleasure without pain: Mr. Maxwell F. N. 940MX (the N stands for Nvidia) played hooky. So I employed the longest envvars ever

$ NVD_LOG=1 VDPAU_TRACE=2 VDPAU_NVIDIA_DEBUG=3 NVD_BACKEND=direct NVD_GPU=nvidia LIBVA_DRIVER_NAME=nvidia VDPAU_DRIVER=nvidia prime-run vdpauinfo
GPU at BusId 0x1 doesn't have a supported video decoder
Error creating VDPAU device: 1
# stfu

to try translating Nvidia VDPAU to VAAPI -- of course, here I realized I rtfmed backwards and should've tried to use just VDPAU instead. So I did.

Juice was still not acquired.

Finally, after a voracious DuckDuckGoing (quacking?), I was then blessed with the freeing knowledge that even though post-Kepler is supposed to support H264, Nvidia is full of lies...

 ______
< fudj >
 ------
          \   ‘^----^‘
           \ (◕(‘人‘)◕)
              (  8    )        ô
              (    8  )_______( )
              ( 8      8        )
              (_________________)
                ||          ||
               (||         (||

and then right before posting this, gut feeling: I can't read.

$ lspci | grep -i nvidia
... NVIDIA Corporation GM108M [GeForce 940MX] (rev a2)
# ArchWiki says that GM108 isn't supported.
# Facepalm

SO. What was your last RTFM adventure?