[Librem 5] PureMaps 3.4.2 Flatpak: Wayland falls back to llvmpipe, QT_QPA_PLATFORM=xcb cannot connect to display

[sokolgeo]

Summary

On a Purism Librem 5 (PureOS Byzantium, Phosh, Wayland), the PureMaps Flatpak 3.4.2 has two problems:

1. Running with the default Wayland backend falls back to llvmpipe (software rendering), making the UI extremely slow.

2. The workaround that worked with previous Flatpak versions

   flatpak override --env=QT_QPA_PLATFORM=xcb io.github.rinigus.PureMaps

   no longer works. With QT_QPA_PLATFORM=xcb, PureMaps now fails with qt.qpa.xcb: could not connect to display, even though Xwayland on the host is working and native X11 apps like xeyes run fine.

So, on this setup there is no way to get GPU accelerated PureMaps via Flatpak anymore: Wayland is software rendered, and xcb cannot connect to X11 inside the sandbox.

---

Environment

• Device: Purism Librem 5
• OS: PureOS Byzantium (arm64)
• Desktop / shell: Phosh (Wayland)
• PureMaps: Flatpak io.github.rinigus.PureMaps 3.4.2 from Flathub
• OSM Scout Server: Flatpak io.github.rinigus.OSMScoutServer
• Flatpak overrides tested:
  • --device=dri
  • --socket=x11, --socket=fallback-x11
  • --share=ipc
  • QT_QPA_PLATFORM=wayland
  • QT_QPA_PLATFORM=xcb

---

What used to work

On earlier PureMaps Flatpak versions the following workaround gave me GPU acceleration, at the cost of a blurry interface via Xwayland:

flatpak override --env=QT_QPA_PLATFORM=xcb io.github.rinigus.PureMaps
flatpak run io.github.rinigus.PureMaps

This produced a much smoother UI (faster map panning and zooming), so I assume it was using the Vivante GPU via etnaviv under Xwayland.

---

Current behavior

1. Wayland path: starts, but uses llvmpipe and is very slow

After resetting overrides and trying Wayland with GPU access:

flatpak override --user --reset io.github.rinigus.PureMaps

flatpak override --user \
  --device=dri \
  --env=QT_QPA_PLATFORM=wayland \
  io.github.rinigus.PureMaps

flatpak run io.github.rinigus.PureMaps

PureMaps starts, but I get the following log output (shortened to the relevant parts):

qt.qpa.qgnomeplatform: Could not find color scheme  ""
Current locale: en_US
Translation not found
Fallback icons at /app/share/io.github.rinigus.PureMaps/qml/icons/fallback
Got library name:  "/app/lib/qml/io/thp/pyotherside/libpyothersideplugin.so"
libEGL warning: failed to get driver name for fd -1

libEGL warning: MESA-LOADER: failed to retrieve device information

libEGL warning: failed to get driver name for fd -1

MESA: error: ZINK: failed to choose pdev
libEGL warning: egl: failed to create dri2 screen
Acquired QGeoPositionInfoSource: "geoclue2"
Calculate direction using a sequence of coordinates
Replacing system-provided Geoclue2 with the bundled plugin
Tracking  "io.github.rinigus.OSMScoutServer"
file:///app/share/io.github.rinigus.PureMaps/qml/PositionSource.qml:71: TypeError: Cannot read property 'center' of null
Translation not found for navigator: "en"
Started DBus service at io.github.rinigus.PureMaps
qml: Initializing voice engine navigator en female
qml: Voice engine: navigator Mimic active=true
qml: Initializing voice engine navigator en female
qml: Voice engine: navigator Mimic active=true
Using QSGMapboxGLTextureNode for map rendering. devicePixelRatio: 2
[ INFO ]  "{unknown}[General]: GPU Identifier: llvmpipe (LLVM 19.1.7, 128 bits)"
Service appeared  "io.github.rinigus.OSMScoutServer"
Map matching active: true

Key line:

GPU Identifier: llvmpipe (LLVM 19.1.7, 128 bits)

So under Wayland the Flatpak ends up rendering via llvmpipe inside the sandbox (software rasterizer). On the Librem 5 this makes map interaction extremely sluggish.

2. xcb/X11 path: no longer works, cannot connect to display

I tried to reapply the old workaround under the current Flatpak:

flatpak override --user --reset io.github.rinigus.PureMaps

QT_QPA_PLATFORM=xcb flatpak run io.github.rinigus.PureMaps

and also with explicit X11 and DRI permission:

flatpak override --user \
  --socket=x11 \
  --socket=fallback-x11 \
  --share=ipc \
  --device=dri \
  io.github.rinigus.PureMaps

DISPLAY=:0 QT_QPA_PLATFORM=xcb flatpak run io.github.rinigus.PureMaps

In all cases I get:

qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, xcb.

With QT_DEBUG_PLUGINS=1:

QT_DEBUG_PLUGINS=1 QT_QPA_PLATFORM=xcb flatpak run io.github.rinigus.PureMaps

I see that Qt finds and loads libqxcb.so, but then fails to connect:

QFactoryLoader::QFactoryLoader() checking directory path "/usr/lib/plugins/platforms" ...
...
QFactoryLoader::QFactoryLoader() looking at "/usr/lib/plugins/platforms/libqxcb.so"
Found metadata in lib /usr/lib/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    ...
}
Got keys from plugin meta data ("xcb")
...
loaded library "/usr/lib/plugins/platforms/libqxcb.so"
qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

So the plugin itself is present and loaded, but there is no usable X11 display inside the sandbox.

---

Host Xwayland status

On the host (Librem 5, same session) Xwayland is working fine:

echo "$DISPLAY"
# :0

echo "$XDG_SESSION_TYPE"
# wayland

xeyes
# works, shows xeyes window on screen

---

Inside the PureMaps Flatpak sandbox

If I open a shell inside the sandbox:

flatpak run --command=sh io.github.rinigus.PureMaps

Then inside the flatpak:

echo "DISPLAY=$DISPLAY"
echo "WAYLAND_DISPLAY=$WAYLAND_DISPLAY"
ls /tmp/.X11-unix 2>/dev/null

I get:

DISPLAY=
WAYLAND_DISPLAY=wayland-0
# /tmp/.X11-unix is empty, no X socket visible

So from inside the sandbox:

• WAYLAND_DISPLAY is set to wayland-0
• DISPLAY is empty
• There is no /tmp/.X11-unix/X0 or similar

In other words, the Flatpak can see Wayland but has no X11 display at all, which explains the qt.qpa.xcb: could not connect to display error.

---

Steps to reproduce on Librem 5

1. On a Librem 5 with PureOS Byzantium and Phosh, install PureMaps Flatpak 3.4.2 from Flathub:

   flatpak install flathub io.github.rinigus.PureMaps io.github.rinigus.OSMScoutServer
   

2. Run PureMaps normally (Wayland backend):

   flatpak run io.github.rinigus.PureMaps
   

   • Observe that it starts, but is very slow.
   • Check log: GPU Identifier: llvmpipe (LLVM ...).

3. Try to force X11 backend with xcb (previous workaround):

   flatpak override --user --reset io.github.rinigus.PureMaps
   
   QT_QPA_PLATFORM=xcb flatpak run io.github.rinigus.PureMaps
   

   or:

   flatpak override --user \
     --socket=x11 \
     --socket=fallback-x11 \
     --share=ipc \
     --device=dri \
     io.github.rinigus.PureMaps
   
   DISPLAY=:0 QT_QPA_PLATFORM=xcb flatpak run io.github.rinigus.PureMaps
   

4. Observe that PureMaps fails to start with qt.qpa.xcb: could not connect to display, even though xeyes works on the host.

---

Expected behavior

• On Librem 5, it should be possible to run PureMaps with GPU acceleration (no llvmpipe) either:

  • via Wayland with a working GLES driver, or
  • via xcb/Xwayland, as the previous Flatpak version allowed using the QT_QPA_PLATFORM=xcb override.

• At minimum, the xcb backend should be able to connect to the host Xwayland display from inside the Flatpak sandbox if --socket=x11 (or x11 / fallback-x11 in the manifest) is granted.

---

Actual behavior

• Wayland backend runs only with llvmpipe inside the Flatpak on Librem 5, making PureMaps very slow.
• xcb backend cannot connect to any X11 display inside the Flatpak sandbox, so the previously working QT_QPA_PLATFORM=xcb workaround no longer works.

---

Question

Is this something that can be adjusted in the Flatpak manifest or runtime used by PureMaps (for example X11 socket / DRI device permissions, or Qt / Mesa configuration for ARM/Librem 5), so that:

• either Wayland gets proper GPU acceleration again, or
• xcb/Xwayland becomes usable again as a workaround on Librem 5?

I am happy to test any experimental Flatpak builds or additional debug env vars on my Librem 5 if that helps track this down.

[rinigus]

Replies: I don't know. Hard to say if any of flatpaks on L5 have acceleration. You would have to investigate it if you want this to be resolved.

[sokolgeo]

Thanks for the reply!

Just to clarify my perspective as a user:

• On the previous PureMaps Flatpak version on this same Librem 5, I was able to get GPU acceleration by using the workaround

  flatpak override --env=QT_QPA_PLATFORM=xcb io.github.rinigus.PureMaps
  flatpak run io.github.rinigus.PureMaps

  The interface was a bit blurred via Xwayland, but it was clearly much faster and usable, so I assume it was using the GPU.

• With the current Flatpak (3.4.2), the same workaround is now broken:

  • QT_QPA_PLATFORM=wayland → PureMaps starts but falls back to llvmpipe (very slow).
  • QT_QPA_PLATFORM=xcb → PureMaps fails with qt.qpa.xcb: could not connect to display, even though Xwayland on the host is working and xeyes runs fine.
  • Inside the sandbox DISPLAY is empty and /tmp/.X11-unix is not visible, which matches the error.

I’ve already shared all the logs and debug output I could gather (QT_DEBUG_PLUGINS=1, overrides, flatpak run --command=sh environment, etc.). As an end user I’m not sure what else I can realistically do on my side beyond:

• Confirming that the old Flatpak + xcb workaround used to work, and
• Showing that with the current Flatpak I can no longer get any accelerated path (Wayland = llvmpipe, xcb = cannot connect to display).

If you think this should now be raised directly with the Flatpak runtime / Flathub / PureOS integration maintainers instead, I’m happy to open an issue there and link back to this one, but from my point of view the only information I have is:

Old Flatpak: QT_QPA_PLATFORM=xcb gave accelerated (but blurry) PureMaps.
New 3.4.2 Flatpak: QT_QPA_PLATFORM=xcb no longer works at all, and Wayland-only runs with llvmpipe.

If there’s any specific extra info or command output you’d still find useful, please let me know and I’ll try to collect it.

[rinigus]

What happened was that Flatpak required changes in flags for a new release: flathub/io.github.rinigus.PureMaps#33

What is changed behind it, how that interferes with L5, why GPU acceleration doesn't work on this platform, I don't know. From L5 start, Pure Maps has been one that is constantly pulled into GPU acceleration on that platform. I suspect that there are either bugs in kernel (has happened before for L5) or somewhere else. At some point, there was an interest in packaging Pure Maps for L5 so it could run directly without Flatpak, but that was never done by L5 users/developers.

On my side, Pure Maps follows the standards of Flatpak packaging and its all I can do on this side.