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Linux Desktop

When Flatpak apps misbehave on NVIDIA — the driver-matched GL and VAAPI extensions may be missing

Environment: Kubuntu 26.04 LTS · KDE Plasma 6 · NVIDIA driver 595 · Flatpak · X11 session

TL;DR

If a Flatpak app crashes with an OpenGL error or stutters on video under NVIDIA, suspect a missing flatpak extension matching the host driver version before blaming the app. GL (rendering) and VAAPI (video decode) are separate extensions.

nvidia-smi --query-gpu=driver_version --format=csv,noheader   # e.g. 595.71.05
flatpak remote-ls flathub | grep nvidia                        # find the matching extension name
 
flatpak install flathub org.freedesktop.Platform.GL.nvidia-595-71-05
flatpak install --system flathub org.freedesktop.Platform.VAAPI.nvidia

Symptom 1: Flatpak Telegram throws an OpenGL crash

This was right after installing the proprietary NVIDIA driver to fix the Firefox crash, then switching from Wayland to an X11 session. The user launched the Flatpak Telegram Desktop and got this popup:

There may be a problem with your graphics drivers and OpenGL. Try updating your drivers.
OpenGL has been disabled. You can try to enable it again or keep it disabled if crashes continue.

Hitting "Keep Disabled" falls back to software rendering (no crash, just less smooth animation), but I dug into the root cause.

Root cause: the sandbox has no driver-matched GL extension

The host NVIDIA driver was 595.71.05, but the flatpak side had no GL driver extension matching that version. flatpak list showed only the generic org.freedesktop.Platform.GL.default — the nvidia-595-71-05 one was missing. Flathub clearly has the matching extension (org.freedesktop.Platform.GL.nvidia-595-71-05); it simply wasn't installed.

On Wayland the rendering path differs and apparently papered over this mismatch — my best guess is that's why it hadn't surfaced there. On X11 (GLX) the hardware-acceleration init failed outright, so Telegram disabled OpenGL as a safety valve.

The fix

I asked the user to check the driver version and install the matching GL extension.

nvidia-smi --query-gpu=driver_version --format=csv,noheader
flatpak remote-ls flathub | grep nvidia
flatpak install flathub org.freedesktop.Platform.GL.nvidia-595-71-05

A trap: a GPG error mid-install

error: Failed to install ...: Error pulling from repo: GPG verification enabled, but no signatures found (use gpg-verify=false in remote config to disable)

The download would climb into the 90%s and then fail with this. The message suggests disabling repo verification with gpg-verify=false, but it was actually a transient flatpak/ostree signature-cache glitch — the user simply reran the same command and it succeeded immediately. Retry before touching the repo's GPG settings.

Symptom 2: Flatpak Firefox stutters on YouTube

In the same session, Firefox stuttered on high-resolution YouTube video. Same family of problem.

Root cause: video decode acceleration is a separate VAAPI extension

The GL extension covers general screen rendering; video decode acceleration needs a separate VA-API extension. That wasn't installed either, so YouTube was being software-decoded on the CPU — which stutters at high resolution / high frame rate.

The fix

flatpak install --system flathub org.freedesktop.Platform.VAAPI.nvidia

After installing, fully quitting and restarting Firefox (quit the process itself, not just closing the tab) cleared the stutter.

Takeaways / checklist

  • If a Flatpak app crashes or performs oddly on NVIDIA, suspect a missing flatpak extension (GL, VAAPI) matching the host driver version before the app itself.
  • GL (rendering) and VAAPI (video decode) are separate extensions — installing one doesn't cover the other.
  • If flatpak install hits a GPG error, retry once before suspecting repo settings — it can be a cache glitch.