Public bug reported:

Summary

The Ubuntu Firefox Snap package fails on an Intel Panther Lake GPU.
After visiting graphics-intensive websites (such as ChatGPT, Claude, or
Google News), Firefox becomes unresponsive to keyboard input and
frequently hangs on exit. The problem is completely resolved by
launching Firefox with:

INTEL_FORCE_PROBE=b080 firefox

or, alternatively,

LIBGL_ALWAYS_SOFTWARE=1 firefox

The official Mozilla Firefox binary (downloaded from mozilla.org) works
normally without either workaround.

System
======
Distribution: Kubuntu 26.04
Kernel: 7.0.0-27-generic
Desktop: KDE Plasma 6.6.5
Session: Wayland
Mesa: 26.0.3-1ubuntu1
GPU: Intel Panther Lake (Arc B390)
PCI ID: 8086
Kernel driver: xe
Hardware

Laptop:
=======
MSI Prestige
Internal display native mode: 2880×1800 @ 120 Hz

Symptoms
========
Initially, Firefox starts normally.

After visiting one of the following sites:

https://chatgpt.com
https://claude.ai
https://news.google.com

Firefox stops responding to keyboard input.

The browser often hangs during exit and must be terminated manually.

Console output
==============
Launching Firefox normally produces:

MESA: error: Intel(R) Graphics (PTL) (0xb080) requires INTEL_FORCE_PROBE
libEGL warning: egl: failed to create dri2 screen
MESA: error: Intel(R) Graphics (PTL) (0xb080) requires INTEL_FORCE_PROBE
MESA: error: ZINK: failed to choose pdev
libEGL warning: egl: failed to create dri2 screen
Diagnostics performed

The following all initialize the Intel GPU successfully:

glxinfo -B
eglinfo
vulkaninfo

No INTEL_FORCE_PROBE environment variable is set.

Workarounds tested
==================
Works
INTEL_FORCE_PROBE=b080 firefox

Firefox functions normally with full hardware acceleration.

LIBGL_ALWAYS_SOFTWARE=1 firefox

Firefox also works using software rendering.

The official Mozilla Firefox tarball downloaded from mozilla.org works
normally without either workaround and does not produce the Mesa errors.

Additional observations
========================
The issue originally appeared immediately after installing available system 
updates.

Testing included:

New Firefox profile
New Linux user account
Firefox Safe Mode
WebRender disabled
WebGPU disabled

None of these changed the behavior.

Why I believe this is not an upstream Firefox bug
=================================================
Mozilla's official Firefox binary works correctly.
The problem appears only with the Ubuntu Firefox Snap.
INTEL_FORCE_PROBE=b080 completely resolves the issue.
The GPU is successfully detected by glxinfo, eglinfo, and vulkaninfo outside 
the failing Firefox startup path.

This suggests the issue is likely in the interaction between the Firefox
Snap runtime, Mesa, and Intel Panther Lake graphics rather than Firefox
itself.

Attachments

Available diagnostic information includes:

inxi -G
glxinfo -B
lspci -nn

inxi -G
=======
Graphics:
  Device-1: Intel Panther Lake [Arc B390] driver: xe v: kernel
  Device-2: Bison FHD Webcam driver: hid-sensor-hub,usbhid,uvcvideo
    type: USB
  Display: wayland server: Xwayland v: 24.1.10 compositor: kwin_wayland
    driver: gpu: xe resolution: 2880x1800~120Hz
  API: EGL v: 1.5 drivers: iris,swrast
    platforms: gbm,wayland,x11,surfaceless,device
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 26.0.3-1ubuntu1
    renderer: Mesa Intel Graphics (PTL)
  API: Vulkan v: 1.4.341 drivers: intel,llvmpipe surfaces: N/A
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo
    de: kscreen-console,kscreen-doctor wl: wayland-info x11: xdriinfo,
    xdpyinfo, xprop, xrandr

glxinfo -B
==========
name of display: :0
display: :0  screen: 0
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel (0x8086)
    Device: Mesa Intel(R) Graphics (PTL) (0xb080)
    Version: 26.0.3
    Accelerated: yes
    Video memory: 31593MB
    Unified memory: yes
    Preferred profile: core (0x1)
    Max core profile version: 4.6
    Max compat profile version: 4.6
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2
OpenGL vendor string: Intel
OpenGL renderer string: Mesa Intel(R) Graphics (PTL)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 26.0.3-1ubuntu1
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile

OpenGL version string: 4.6 (Compatibility Profile) Mesa 26.0.3-1ubuntu1
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile

OpenGL ES profile version string: OpenGL ES 3.2 Mesa 26.0.3-1ubuntu1
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20

lspci -nn
=========
00:00.0 Host bridge [0600]: Intel Corporation Device [8086:b001] (rev 04)
00:02.0 VGA compatible controller [0300]: Intel Corporation Panther Lake [Arc 
B390] [8086:b080] (rev 04)
00:04.0 Signal processing controller [1180]: Intel Corporation Panther Lake 
Innovation Platform Framework Processor Participant [8086:b01d] (rev 04)
00:06.0 PCI bridge [0604]: Intel Corporation Device [8086:e461] (rev 01)
00:07.0 PCI bridge [0604]: Intel Corporation Device [8086:e460] (rev 01)
00:07.3 PCI bridge [0604]: Intel Corporation Device [8086:e437] (rev 01)
00:0a.0 Signal processing controller [1180]: Intel Corporation Panther Lake 
Platform Monitoring Technology (PMT) [8086:b07d] (rev 04)
00:0b.0 Processing accelerators [1200]: Intel Corporation Panther Lake NPU 
[8086:b03e] (rev 04)
00:0d.0 USB controller [0c03]: Intel Corporation Device [8086:e431] (rev 01)
00:0d.3 USB controller [0c03]: Intel Corporation Device [8086:e434] (rev 01)
00:12.0 Serial controller [0700]: Intel Corporation Device [8086:e445] (rev 01)
00:13.0 Communication controller [0780]: Intel Corporation Device [8086:e462] 
(rev 01)
00:14.0 USB controller [0c03]: Intel Corporation Device [8086:e47d] (rev 01)
00:14.2 RAM memory [0500]: Intel Corporation Device [8086:e47f] (rev 01)
00:14.3 Network controller [0280]: Intel Corporation Device [8086:e440] (rev 01)
00:14.7 Bluetooth [0d11]: Intel Corporation Device [8086:e476] (rev 01)
00:16.0 Communication controller [0780]: Intel Corporation Device [8086:e470] 
(rev 01)
00:18.0 Communication controller [0780]: Intel Corporation Device [8086:e45d] 
(rev 01)
00:19.0 Serial bus controller [0c80]: Intel Corporation Device [8086:e450] (rev 
01)
00:19.1 Serial bus controller [0c80]: Intel Corporation Device [8086:e451] (rev 
01)
00:1f.0 ISA bridge [0601]: Intel Corporation Device [8086:e402] (rev 01)
00:1f.3 Multimedia audio controller [0401]: Intel Corporation Device 
[8086:e428] (rev 01)
00:1f.4 SMBus [0c05]: Intel Corporation Device [8086:e422] (rev 01)
00:1f.5 Serial bus controller [0c80]: Intel Corporation Device [8086:e423] (rev 
01)
01:00.0 Non-Volatile memory controller [0108]: Micron Technology Inc 2500 NVMe 
SSD (DRAM-less) [1344:5425] (rev 01)
02:00.0 PCI bridge [0604]: Intel Corporation Thunderbolt 4 Bridge [Goshen Ridge 
2020] [8086:0b26] (rev 03)
03:00.0 PCI bridge [0604]: Intel Corporation Thunderbolt 4 Bridge [Goshen Ridge 
2020] [8086:0b26] (rev 03)
03:01.0 PCI bridge [0604]: Intel Corporation Thunderbolt 4 Bridge [Goshen Ridge 
2020] [8086:0b26] (rev 03)
03:02.0 PCI bridge [0604]: Intel Corporation Thunderbolt 4 Bridge [Goshen Ridge 
2020] [8086:0b26] (rev 03)
03:03.0 PCI bridge [0604]: Intel Corporation Thunderbolt 4 Bridge [Goshen Ridge 
2020] [8086:0b26] (rev 03)
03:04.0 PCI bridge [0604]: Intel Corporation Thunderbolt 4 Bridge [Goshen Ridge 
2020] [8086:0b26] (rev 03)

lsb_release -rd
===============
Description:    Ubuntu 26.04 LTS
Release:        26.04

Thank you,
Chris Strawser
[email protected]

** Affects: firefox (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/2159393

Title:
  Firefox Snap fails on Intel Panther Lake (8086) unless
  INTEL_FORCE_PROBE is set

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