SSAO broken on Linux with Intel Arc Graphics

[PerAstraAdDeum]

Hi there,

I tried the recently-verified RBDOOM on Flatpak on my Intel Ultra notebook and noticed that SSAO is broken. See the following screenshots:

Menu and loading screen are just fine, actual game shows heavily artifacts though. Disabling SSAO is a workaround for this.

Sytem:
CPU: Intel Core Ultra 155H
iGPU: Intel Arc Graphics
RAM: 64GB DDR5 SO-DIMM
OS: Secureblue (Based on Fedora Atomic)
Install: Flatpak

Tested the same on my desktop system (7950X3D, 7900 XTX, also Flatpak on Fedora Atomic) and it seems like it's just working fine with AMD.

Best regards

[runlevel5]

Could you please provide more information on the Linux kernel version and whether you are using the xe or i915 driver module?

[PerAstraAdDeum]

Could you please provide more information on the Linux kernel version and whether you are using the xe or i915 driver module?

Sure, Kernel version is 6.16.7-200.fc42.x86_64, and I've tried it with i915 and xe driver, the issue is the same on both.

[runlevel5]

@PerAstraAdDeum does the issue happen on non-flatpack version of the game?

[PerAstraAdDeum]

@PerAstraAdDeum does the issue happen on non-flatpack version of the game?

Sorry, tried compiling the game but it fails at step 4 with

CMake Error at extern/ShaderMake/CMakeLists.txt:144 (message):
  Can't find DXC: Specify custom path using 'DXC_CUSTOM_PATH' parameter or
  install VulkanSDK!

I don't know how to fix that, sorry :-(

[runlevel5]

@PerAstraAdDeum you need to follow the instructions

[PerAstraAdDeum]

@PerAstraAdDeum you need to follow the instructions

Yes, thank you, I've tried that ("fails at step 4"). It seems like compat-ffmpeg4-devel is not available on Fedora Atomic, however the error suggests installing VulkanSDK, which isn't available on Fedora Atomic either, so that's probably not related.
I've tried installing vulkan-tools and vulkan-devel, however the compiling still fails with the aforementioned error.

[runlevel5]

@PerAstraAdDeum

Yes, thank you, I've tried that ("fails at step 4"). It seems like compat-ffmpeg4-devel is not available on Fedora Atomic

The doc might be out of date, you should install ffmpeg-devel or ffmpeg-free-devel (depending on the FFMPEG version you are using).

[PerAstraAdDeum]

@PerAstraAdDeum

Yes, thank you, I've tried that ("fails at step 4"). It seems like compat-ffmpeg4-devel is not available on Fedora Atomic

The doc might be out of date, you should install ffmpeg-devel or ffmpeg-free-devel (depending on the FFMPEG version you are using).

Hi, I gave that a try and installed ffmpeg-devel. The issue persists though. Installing ffmpeg-free-devel didn't work:

error: Could not depsolve transaction; 1 problem detected:
 Problem: conflicting requests
  - package ffmpeg-free-devel-7.1.1-4.fc42.i686 from updates requires libavcodec-free-devel = 7.1.1-4.fc42, but none of the providers can be installed
  - package ffmpeg-free-devel-7.1.1-4.fc42.x86_64 from updates requires libavcodec-free-devel = 7.1.1-4.fc42, but none of the providers can be installed
  - package ffmpeg-free-devel-7.1.1-4.fc42.x86_64 from updates-archive requires libavcodec-free-devel = 7.1.1-4.fc42, but none of the providers can be installed
  - package ffmpeg-free-devel-7.1.1-3.fc42.i686 from fedora requires libavcodec-free-devel = 7.1.1-3.fc42, but none of the providers can be installed
  - package ffmpeg-free-devel-7.1.1-3.fc42.x86_64 from fedora requires libavcodec-free-devel = 7.1.1-3.fc42, but none of the providers can be installed
  - package libavcodec-free-devel-7.1.1-4.fc42.i686 from updates requires libavcodec-free(x86-32) = 7.1.1-4.fc42, but none of the providers can be installed
  - package libavcodec-free-devel-7.1.1-4.fc42.x86_64 from updates requires libavcodec-free(x86-64) = 7.1.1-4.fc42, but none of the providers can be installed
  - package libavcodec-free-devel-7.1.1-4.fc42.x86_64 from updates-archive requires libavcodec-free(x86-64) = 7.1.1-4.fc42, but none of the providers can be installed
  - package libavcodec-free-devel-7.1.1-3.fc42.i686 from fedora requires libavcodec-free(x86-32) = 7.1.1-3.fc42, but none of the providers can be installed
  - package libavcodec-free-devel-7.1.1-3.fc42.x86_64 from fedora requires libavcodec-free(x86-64) = 7.1.1-3.fc42, but none of the providers can be installed
  - installed package libavcodec-1:7.1.2-1.fc42.x86_64 obsoletes libavcodec-free < 1:7.1.2-1.fc42 provided by libavcodec-free-7.1.1-4.fc42.i686 from updates
  - installed package libavcodec-1:7.1.2-1.fc42.x86_64 obsoletes libavcodec-free < 1:7.1.2-1.fc42 provided by libavcodec-free-7.1.1-4.fc42.x86_64 from updates
  - installed package libavcodec-1:7.1.2-1.fc42.x86_64 obsoletes libavcodec-free < 1:7.1.2-1.fc42 provided by libavcodec-free-7.1.1-3.fc42.i686 from fedora
  - installed package libavcodec-1:7.1.2-1.fc42.x86_64 obsoletes libavcodec-free < 1:7.1.2-1.fc42 provided by libavcodec-free-7.1.1-3.fc42.x86_64 from fedora
  - installed package libavcodec-1:7.1.2-1.fc42.x86_64 obsoletes libavcodec-free < 1:7.1.2-1.fc42 provided by libavcodec-free-7.1.1-4.fc42.x86_64 from updates-archive

Shouldn't the issue lie with Vulkan though?

[runlevel5]

Could you please paste the error message here?

[PerAstraAdDeum]

Could you please paste the error message here?

Sure. Running ./cmake-linux-release.sh in /DoomCode/neo outputs:

-- The C compiler identification is GNU 15.2.1
-- The CXX compiler identification is GNU 15.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/sbin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/sbin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_BUILD_TYPE:Release
-- Performing Test COMPILER_SUPPORTS_CXX17
-- Performing Test COMPILER_SUPPORTS_CXX17 - Success
-- Using module to find Vulkan and components
-- Found Vulkan: /lib64/libvulkan.so (found version "1.4.313")  missing components: dxc glslc glslangValidator
-- Using Vulkan: /lib64/libvulkan.so
CMake Error at extern/ShaderMake/CMakeLists.txt:144 (message):
  Can't find DXC: Specify custom path using 'DXC_CUSTOM_PATH' parameter or
  install VulkanSDK!


-- Configuring incomplete, errors occurred!

[runlevel5]

@PerAstraAdDeum

Can't find DXC: Specify custom path using 'DXC_CUSTOM_PATH' parameter or

That means you have not done the step 1:

Go to https://github.com/microsoft/DirectXShaderCompiler/releases/tag/v1.8.2405 and download the DXC binaries for Linux and put them into your local PATH.

that basically means:

wget https://github.com/microsoft/DirectXShaderCompiler/releases/download/v1.8.2405/linux_dxc_2024_05_24.x86_64.tar.gz
mkdir -p ~/.local
tar xzvf linux_dxc_2024_05_24.x86_64.tar.gz -C ~/.local/
chmod +x ~/.local/bin/dxc
export PATH=~/.local/bin:$PATH

[PerAstraAdDeum]

@PerAstraAdDeum

Can't find DXC: Specify custom path using 'DXC_CUSTOM_PATH' parameter or

That means you have not done the step 1:

Go to https://github.com/microsoft/DirectXShaderCompiler/releases/tag/v1.8.2405 and download the DXC binaries for Linux and put them into your local PATH.

that basically means:

wget https://github.com/microsoft/DirectXShaderCompiler/releases/download/v1.8.2405/linux_dxc_2024_05_24.x86_64.tar.gz
mkdir -p ~/.local
tar xzvf linux_dxc_2024_05_24.x86_64.tar.gz -C ~/.local/
chmod +x ~/.local/bin/dxc
export PATH=~/.local/bin:$PATH

Thank you. You very right. I missed that step.

I've re-done that now and followed all the steps from the instruction and built the game. Starting doesn't work however:

QA Timing INIT: 000521ms
RBDOOM 3 BFG 1.6.0.1403 linux-x86_64 Sep 23 2025 02:14:40
found interface lo - loopback
found interface eno0 - 192.168.178.63/255.255.255.0
found interface virbr0 - 192.168.122.1/255.255.255.0
------ Initializing File System ------
Loaded resource file _common.resources
Loaded resource file _ordered.resources
Loaded resource file _sound_pc.resources
Loaded resource file _sound_pc_en.resources
Loaded resource file _sound_pc_fr.resources
Loaded resource file _sound_pc_gr.resources
Loaded resource file _sound_pc_it.resources
Loaded resource file _sound_pc_jp.resources
Loaded resource file _sound_pc_sp.resources
Loaded zip file /var/home/user/DoomCode/base/_rbdoom_blood.pk4
Loaded pk4 /var/home/user/DoomCode/base/_rbdoom_blood.pk4 with checksum 0xa84b3629
Loaded zip file /var/home/user/DoomCode/base/_rbdoom_core.pk4
Loaded pk4 /var/home/user/DoomCode/base/_rbdoom_core.pk4 with checksum 0xe992ec24
Loaded zip file /var/home/user/DoomCode/base/_rbdoom_global_illumination_data.pk4
Loaded pk4 /var/home/user/DoomCode/base/_rbdoom_global_illumination_data.pk4 with checksum 0x37570a4d
Loaded resource file maps/admin.resources
Loaded resource file maps/alphalabs1.resources
Loaded resource file maps/alphalabs2.resources
Loaded resource file maps/alphalabs3.resources
Loaded resource file maps/alphalabs4.resources
Loaded resource file maps/caverns1.resources
Loaded resource file maps/caverns2.resources
Loaded resource file maps/comm1.resources
Loaded resource file maps/commoutside.resources
Loaded resource file maps/cpu.resources
Loaded resource file maps/cpuboss.resources
Loaded resource file maps/d3ctf1.resources
Loaded resource file maps/d3ctf2.resources
Loaded resource file maps/d3ctf3.resources
Loaded resource file maps/d3ctf4.resources
Loaded resource file maps/d3dm1.resources
Loaded resource file maps/d3dm2.resources
Loaded resource file maps/d3dm3.resources
Loaded resource file maps/d3dm4.resources
Loaded resource file maps/d3dm5.resources
Loaded resource file maps/d3xpdm1.resources
Loaded resource file maps/d3xpdm2.resources
Loaded resource file maps/d3xpdm3.resources
Loaded resource file maps/d3xpdm4.resources
Loaded resource file maps/delta1.resources
Loaded resource file maps/delta2a.resources
Loaded resource file maps/delta2b.resources
Loaded resource file maps/delta3.resources
Loaded resource file maps/delta4.resources
Loaded resource file maps/delta5.resources
Loaded resource file maps/deltax.resources
Loaded resource file maps/enpro.resources
Loaded resource file maps/erebus1.resources
Loaded resource file maps/erebus2.resources
Loaded resource file maps/erebus3.resources
Loaded resource file maps/erebus4.resources
Loaded resource file maps/erebus5.resources
Loaded resource file maps/erebus6.resources
Loaded resource file maps/hell.resources
Loaded resource file maps/hell1.resources
Loaded resource file maps/hellhole.resources
Loaded resource file maps/le_enpro1.resources
Loaded resource file maps/le_enpro2.resources
Loaded resource file maps/le_exis1.resources
Loaded resource file maps/le_exis2.resources
Loaded resource file maps/le_hell.resources
Loaded resource file maps/le_hell_post.resources
Loaded resource file maps/le_underground.resources
Loaded resource file maps/le_underground2.resources
Loaded resource file maps/mars_city1.resources
Loaded resource file maps/mars_city2.resources
Loaded resource file maps/mc_underground.resources
Loaded resource file maps/monorail.resources
Loaded resource file maps/phobos1.resources
Loaded resource file maps/phobos2.resources
Loaded resource file maps/phobos3.resources
Loaded resource file maps/phobos4.resources
Loaded resource file maps/recycling1.resources
Loaded resource file maps/recycling2.resources
Loaded resource file maps/site3.resources
Current search path:
/var/home/user/.local/share/rbdoom3bfg/base
/var/home/user/DoomCode/base
/var/home/user/DoomCode/base/_rbdoom_global_illumination_data.pk4 (12294 files)
/var/home/user/DoomCode/base/_rbdoom_core.pk4 (663 files)
/var/home/user/DoomCode/base/_rbdoom_blood.pk4 (166 files)
/var/home/user/DoomCode/base/maps/site3.resources (1725 files)
/var/home/user/DoomCode/base/maps/recycling2.resources (1528 files)
/var/home/user/DoomCode/base/maps/recycling1.resources (1657 files)
/var/home/user/DoomCode/base/maps/phobos4.resources (2168 files)
/var/home/user/DoomCode/base/maps/phobos3.resources (2551 files)
/var/home/user/DoomCode/base/maps/phobos2.resources (2792 files)
/var/home/user/DoomCode/base/maps/phobos1.resources (2750 files)
/var/home/user/DoomCode/base/maps/monorail.resources (2190 files)
/var/home/user/DoomCode/base/maps/mc_underground.resources (2365 files)
/var/home/user/DoomCode/base/maps/mars_city2.resources (2639 files)
/var/home/user/DoomCode/base/maps/mars_city1.resources (2721 files)
/var/home/user/DoomCode/base/maps/le_underground2.resources (2325 files)
/var/home/user/DoomCode/base/maps/le_underground.resources (1918 files)
/var/home/user/DoomCode/base/maps/le_hell_post.resources (1170 files)
/var/home/user/DoomCode/base/maps/le_hell.resources (1057 files)
/var/home/user/DoomCode/base/maps/le_exis2.resources (2674 files)
/var/home/user/DoomCode/base/maps/le_exis1.resources (2579 files)
/var/home/user/DoomCode/base/maps/le_enpro2.resources (1980 files)
/var/home/user/DoomCode/base/maps/le_enpro1.resources (2280 files)
/var/home/user/DoomCode/base/maps/hellhole.resources (1312 files)
/var/home/user/DoomCode/base/maps/hell1.resources (1200 files)
/var/home/user/DoomCode/base/maps/hell.resources (1125 files)
/var/home/user/DoomCode/base/maps/erebus6.resources (1818 files)
/var/home/user/DoomCode/base/maps/erebus5.resources (1986 files)
/var/home/user/DoomCode/base/maps/erebus4.resources (2659 files)
/var/home/user/DoomCode/base/maps/erebus3.resources (2891 files)
/var/home/user/DoomCode/base/maps/erebus2.resources (2115 files)
/var/home/user/DoomCode/base/maps/erebus1.resources (1704 files)
/var/home/user/DoomCode/base/maps/enpro.resources (2124 files)
/var/home/user/DoomCode/base/maps/deltax.resources (2491 files)
/var/home/user/DoomCode/base/maps/delta5.resources (2148 files)
/var/home/user/DoomCode/base/maps/delta4.resources (1076 files)
/var/home/user/DoomCode/base/maps/delta3.resources (2326 files)
/var/home/user/DoomCode/base/maps/delta2b.resources (2333 files)
/var/home/user/DoomCode/base/maps/delta2a.resources (2432 files)
/var/home/user/DoomCode/base/maps/delta1.resources (2299 files)
/var/home/user/DoomCode/base/maps/d3xpdm4.resources (303 files)
/var/home/user/DoomCode/base/maps/d3xpdm3.resources (290 files)
/var/home/user/DoomCode/base/maps/d3xpdm2.resources (339 files)
/var/home/user/DoomCode/base/maps/d3xpdm1.resources (476 files)
/var/home/user/DoomCode/base/maps/d3dm5.resources (957 files)
/var/home/user/DoomCode/base/maps/d3dm4.resources (1152 files)
/var/home/user/DoomCode/base/maps/d3dm3.resources (987 files)
/var/home/user/DoomCode/base/maps/d3dm2.resources (961 files)
/var/home/user/DoomCode/base/maps/d3dm1.resources (1215 files)
/var/home/user/DoomCode/base/maps/d3ctf4.resources (1027 files)
/var/home/user/DoomCode/base/maps/d3ctf3.resources (1079 files)
/var/home/user/DoomCode/base/maps/d3ctf2.resources (1099 files)
/var/home/user/DoomCode/base/maps/d3ctf1.resources (690 files)
/var/home/user/DoomCode/base/maps/cpuboss.resources (1773 files)
/var/home/user/DoomCode/base/maps/cpu.resources (1862 files)
/var/home/user/DoomCode/base/maps/commoutside.resources (2205 files)
/var/home/user/DoomCode/base/maps/comm1.resources (2493 files)
/var/home/user/DoomCode/base/maps/caverns2.resources (1077 files)
/var/home/user/DoomCode/base/maps/caverns1.resources (1595 files)
/var/home/user/DoomCode/base/maps/alphalabs4.resources (2157 files)
/var/home/user/DoomCode/base/maps/alphalabs3.resources (1701 files)
/var/home/user/DoomCode/base/maps/alphalabs2.resources (2327 files)
/var/home/user/DoomCode/base/maps/alphalabs1.resources (2334 files)
/var/home/user/DoomCode/base/maps/admin.resources (2148 files)
/var/home/user/DoomCode/base/_sound_pc_sp.resources (825 files)
/var/home/user/DoomCode/base/_sound_pc_jp.resources (831 files)
/var/home/user/DoomCode/base/_sound_pc_it.resources (830 files)
/var/home/user/DoomCode/base/_sound_pc_gr.resources (830 files)
/var/home/user/DoomCode/base/_sound_pc_fr.resources (825 files)
/var/home/user/DoomCode/base/_sound_pc_en.resources (840 files)
/var/home/user/DoomCode/base/_sound_pc.resources (4759 files)
/var/home/user/DoomCode/base/_ordered.resources (1336 files)
/var/home/user/DoomCode/base/_common.resources (2262 files)
file system initialized.
--------------------------------------
fatal allocator error: sized deallocation mismatch (small)
signal caught: Aborted
si_code -6
Trying to exit gracefully..
session->GetSaveGameManager().CancelToTerminate();
soundSystem->StopAllSounds();
Stop();
--------- Game Map Shutdown ----------
--------------------------------------
CleanupShell();
delete loadGUI;
ImGuiHook::Destroy();
delete renderWorld;
delete soundWorld;
delete menuSoundWorld;
session->ShutdownSoundRelatedSystems();
session->Shutdown();
game->Leaderboards_Shutdown();
uiManager->Shutdown();
usercmdGen->Shutdown();
eventLoop->Shutdown();
declManager->Shutdown();
renderSystem->Shutdown();
idRenderSystem::Shutdown()
double fault Segmentation fault, bailing out

What is missing here?

[SRSaunders]

@PerAstraAdDeum I am not sure what is wrong with your local build. However, using the flatpak build you could try setting r_useNewSSAOPass 0 in the console (in game) or in your autoexec.cfg file (as a sticky setting). This would still provide an SSAO effect, but would be based on an older SSAO technology still present in the game. Let me know if that works.

Note the flatpak build is based on the rpsubsets-and-pc branch of this repo, which gives faster performance on Vulkan for linux and macOS. If you are building using master, you may not get max Vulkan performance.

[SRSaunders]

@PerAstraAdDeum re your local build: Perhaps the Secureblue distro is using a hardened memory allocator that enforces strict matching of deallocations to allocation sizes. I would be interested in seeing where this mismatch occurs in the code.

Would you be able to build a debug version and start the game in a debugger? I would like to know the specific module and line number where the deallocation fails to match. Thanks.

I have worked hard to find and remove most memory leaks, but I guess there could be more out there...

[PerAstraAdDeum]

@SRSaunders sorry for the late reply. Trying to address all your points here:

However, using the flatpak build you could try setting r_useNewSSAOPass 0 in the console (in game) or in your autoexec.cfg file (as a sticky setting). This would still provide an SSAO effect, but would be based on an older SSAO technology still present in the game. Let me know if that works.

That works.

Perhaps the Secureblue distro is using a hardened memory allocator that enforces strict matching of deallocations to allocation sizes.

I'm running the game without the hardened memalloc. It won't start with it being enabled.

Would you be able to build a debug version and start the game in a debugger?

I think so? You'd have to guide me through the process though.