Notes | ROCKNIX Steam Compatibility DB

File index

Relevant ROCKNIX and Steam files

/storage/.config/system/configs/system.cfg: EmulationStation's per-game Steam settings, including Steam arch, host-library toggles, and gamescope.
/storage/.local/share/applications/<desktop-file>: The launcher filename used inside steam["<desktop-file>"] keys. Match the existing file name exactly.
/storage/.local/share/Steam/config/config.vdf: Steam's per-game compatibility-tool mapping. This is where the selected Proton or Steam Native tool id is stored for an app.
/storage/.local/share/Steam/compatibilitytools.d/: Custom/local compatibility tools folder. Use compatibilitytool.vdf here for non-official tools only.
/storage/.local/share/Steam/steamapps/common/<Proton tool>/toolmanifest.vdf: Official Steam Proton tool manifest. Its require_tool_appid points to the required Steam Linux Runtime app.
/storage/.local/share/Steam/steamapps/appmanifest_<runtime-appid>.acf: Steam app manifest for the runtime app. Use installdir to map the runtime appid to its folder.
/storage/.local/share/Steam/steamapps/common/<runtime installdir>/toolmanifest.vdf: Steam Linux Runtime manifest. compatmanager_layer_name confirms the runtime layer, such as container-runtime.
/storage/.local/share/Steam/userdata/<user-id>/config/localconfig.vdf: Steam launch options for a user profile, including PROTON_LOG=1 %command%.
/storage/steam-<appid>.log: Per-game Proton log created after Proton logging is enabled and the game starts.
/storage/.local/share/Steam/logs/gameprocess_log.txt: Steam-side launch log for cases where Steam starts but the game or Proton does not clearly run.
/storage/.local/share/Steam/logs/console-linux.txt: Steam client messages for compatibility-tool, library, and general client behavior.
/storage/.local/share/Steam/logs/webhelper-linux.txt: Steam webhelper messages for Steam UI, embedded pages, and launcher web views.
/var/log/exec.log: EmulationStation launch routing log for failures before Steam takes over.

These are the files to know before troubleshooting. Start in the UI when possible, then use the matching path above to confirm what changed.

Example: HELLDIVERS 2

/storage/.local/share/applications/HELLDIVERS™ 2.desktop
/storage/steam-553850.log

Caution: If you modify Steam files via SSH for scripted launch, make sure Steam is not already running so settings can take effect.

ROCKNIX host libraries

Choose Steam x86 or ARM and Host Libraries before the game starts

Use this when you want ROCKNIX to launch a Steam game through x86 or ARM Steam, or when you need to compare host-library toggles before the game starts.

Manual instructions: Navigate to your Steam game in ROCKNIX, press the NORTH button on the controller to open Advanced Settings, then adjust these per-game values before launching Steam.

These ROCKNIX keys belong in /storage/.config/system/configs/system.cfg and are applied per game before Steam starts. The part inside brackets is the desktop launcher filename, not the game title you type from memory. Some setups also mirror values to steam["Steam.desktop"].steam_version=; that mirror is still in system.cfg, not inside the desktop file.

steam_version: Steam architecture path. Use x86 for x86 Steam or arm64 for ARM Steam.
vulkan_host_library: Host Vulkan libraries. Usually 1 for Vulkan, DXVK, and VKD3D games. Try 0 only after recording a baseline.
drm_host_library: Host DRM/libdrm path. Usually 0. Try 1 for display, GPU device, or gamescope isolation.
gl_host_library: Host OpenGL libraries. Usually 0. Try 1 for OpenGL launchers or helper windows.
wayland_client_host_library: Host Wayland client libraries. Usually 0. Try 1 for compositor, windowing, focus, or gamescope issues.
asound_host_library: Host ALSA/asound libraries. Usually 0. Try 1 for audio device, crackle, or latency problems.
gamescope: Handheld Steam compositor path. Usually 1 for normal ROCKNIX Steam launches.

Example: HELLDIVERS 2

steam["HELLDIVERS™ 2.desktop"].steam_version=arm64
steam["HELLDIVERS™ 2.desktop"].vulkan_host_library=1
steam["HELLDIVERS™ 2.desktop"].drm_host_library=0
steam["HELLDIVERS™ 2.desktop"].gl_host_library=0
steam["HELLDIVERS™ 2.desktop"].wayland_client_host_library=0
steam["HELLDIVERS™ 2.desktop"].asound_host_library=0
steam["HELLDIVERS™ 2.desktop"].gamescope=1

Helper notes for automated Steam game testing

Test one thing at a time. Start with a baseline, then change one variable so runtime, Steam arch, host libraries, and launch options do not blur together.

Resource snapshot

#resource_snapshot

Capture CPU, GPU, RAM, zram, thermals, and kernel clues

uptime#Load average and uptime

free -h#RAM and swap overview

zramctl#Zram DATA, COMPR, TOTAL, and DISKSIZE

ps -eo pid,ppid,stat,wchan,etime,pcpu,pmem,rss,comm,args --sort=-pcpu | head -20#Top CPU and wait-state processes

ps -eo pid,ppid,stat,wchan,etime,pcpu,pmem,rss,comm,args --sort=-rss | head -15#Top RAM/RSS processes

cat /sys/class/kgsl/kgsl-3d0/gpu_busy_percentage#Adreno GPU busy percentage

cat /sys/class/kgsl/kgsl-3d0/cur_freq#Adreno GPU current frequency

cat /sys/class/thermal/thermal_zone*/type#Thermal sensor names

cat /sys/class/thermal/thermal_zone*/temp#Thermal sensor readings

dmesg | tail -80#Recent kernel faults, OOM, GPU, DRM, and IO lines

Run a quick snapshot while the game is running, hung, or immediately after it exits. Record RAM, zram, top CPU/RSS processes, blocked or waiting process clues from wchan, GPU load or frequency, thermals, and any fresh kernel fault lines.

zramctl is more useful than swap-used alone: DATA is real uncompressed payload, COMPR is compressed size, TOTAL is allocator usage, and DISKSIZE is capacity.

These commands come from the RP6 reference scripts. If one path is missing on your build, write not available and keep the rest of the snapshot. Do not change test settings just to make the snapshot cleaner.

Example: HELLDIVERS 2

Usage: RAM used 5.2G / available 1.1G; zram DATA 1.8G, COMPR 650M, TOTAL 760M; HELLDIVERS 2 RSS 3.4G; GPU busy 82%; thermals stable; new dmesg faults no.

Log triage

#log_triage

Check logs in the order the launch failed

/storage/steam-<appid>.log
/storage/.local/share/Steam/logs/gameprocess_log.txt
/storage/.local/share/Steam/logs/console-linux.txt
/storage/.local/share/Steam/logs/webhelper-linux.txt
/var/log/exec.log

/storage/steam-<appid>.logProton reached the game or launcher.
/storage/.local/share/Steam/logs/gameprocess_log.txtSteam launched, but Proton or the app did not clearly start.
/storage/.local/share/Steam/logs/console-linux.txtSteam client messages for compatibility-tool, library, and general client behavior.
/storage/.local/share/Steam/logs/webhelper-linux.txtSteam UI, embedded page, or launcher web view messages.
/var/log/exec.logEmulationStation launch routing failed before Steam took over.

Use the Proton log if the game or launcher starts under Proton.
Use Steam logs if Steam opens but the handoff to Proton or the app is unclear.
Use /var/log/exec.log if the launch never reaches Steam.

Example: HELLDIVERS 2

/storage/steam-553850.log
/storage/.local/share/Steam/logs/gameprocess_log.txt
/storage/.local/share/Steam/logs/console-linux.txt
/storage/.local/share/Steam/logs/webhelper-linux.txt
/var/log/exec.log

Display reset

#display_input_reset

Reset display/input only if the old frame remains

systemctl stop essway.service sway.service emustation.service
systemctl restart seatd.service
systemctl start essway.service

Use this when Steam has stopped but ROCKNIX still shows a stale frame. It resets the frontend display/input path by stopping the possible Sway or EmulationStation services, restarting seatd.service, then starting essway.service again.

Frame pacing

#mangohud_frame_limit

Try MangoHud's frame limiter for steadier pacing

MANGOHUD=1 MANGOHUD_CONFIG=fps_limit=30 %command%

If Gamescope's frame limiter feels uneven, cap the game with MangoHud from Steam Launch Options instead. The target FPS can be changed, but keep %command% at the end so Steam still runs the game.

This is useful when a 30 FPS cap still shows pacing spikes, stutter, or jumps above the cap. Treat it as one test variable and compare it against the same game, runtime, and graphics settings.

Example: NieR:Automata at 30 FPS

"524220"
{
  "LaunchOptions"  "MANGOHUD=1 MANGOHUD_CONFIG=fps_limit=30 %command%"
}

Tip credit: hugare on Discord, after noticing NieR:Automata stutters with Gamescope's 30 FPS limiter and spikes around 33-34 FPS.

Graphics artifacts

#graphics_artifacts

Try TU_DEBUG=nolrz for flicker, black textures, or broken shadows

TU_DEBUG=nolrz %command%

TU_DEBUG is Mesa Turnip's debug setting for Qualcomm Adreno Vulkan. nolrz disables LRZ, the low-resolution depth rejection path that helps the GPU skip hidden pixels earlier.

Use it when a game launches but has flickering geometry, black textures, broken shadow maps, or depth-related artifacts. It can cost performance, so treat it as one test variable and remove it if it does not clearly help.

Example: HELLDIVERS 2

"553850"
{
  "LaunchOptions"  "TU_DEBUG=nolrz %command%"
}

Custom Proton tools

#custom_proton_tools

Place local Proton builds in compatibilitytools.d

/storage/.local/share/Steam/compatibilitytools.d/
/storage/.local/share/Steam/compatibilitytools.d/<custom-proton-folder>/
/storage/.local/share/Steam/compatibilitytools.d/<custom-proton-folder>/compatibilitytool.vdf

This folder is for custom or local compatibility tools, such as community Proton builds or device-specific ARM Proton tools. The compatibilitytool.vdf file belongs inside the custom tool's folder. Official Steam Proton tools use their own toolmanifest.vdf lookup instead.

"compat_tools"
{
  "<custom-tool-id>"
  {
    "display_name"  "<custom Proton name>"
  }
  }
}

Launch game

#launch_game

Launch from EmulationStation for comparable results

/storage/.local/share/applications/<desktop-file>
/usr/bin/runemu.sh "/storage/.local/share/applications/<desktop-file>" -Psteam --core=steam --emulator=steam

The desktop file is the launcher name EmulationStation uses. Launching through EmulationStation applies the per-game system.cfg settings and the ROCKNIX Steam wrapper. The runemu.sh command is useful for scripted launches because it still uses that ROCKNIX path.

A bare Steam URL launch can skip parts of that path, so avoid it when comparing reports or troubleshooting host-library settings.

Example: HELLDIVERS 2

/storage/.local/share/applications/HELLDIVERS™ 2.desktop
/usr/bin/runemu.sh "/storage/.local/share/applications/HELLDIVERS™ 2.desktop" -Psteam --core=steam --emulator=steam

Steam desktop mode

#steam_desktop_mode

Open regular Steam instead of Big Picture

/storage/.config/system/configs/system.cfg
steam["<desktop-file>"].steam_version=x86
steam["<desktop-file>"].gamescope=0

Use the same ROCKNIX Advanced Settings screen where you choose the Steam version. Set the Steam version you want, such as x86, then turn Gamescope off so Steam launches in the regular desktop interface instead of Big Picture mode.

Manual instructions: Navigate to the Steam game in ROCKNIX, press NORTH to open Advanced Settings, confirm the Steam version, then set Gamescope to off before launching.

Desktop Steam is easier for some compatibility setup and debugging, but controller navigation can be rough. Depending on your device, plug in a USB mouse so you can reach Steam menus reliably.

Example: HELLDIVERS 2

steam["HELLDIVERS™ 2.desktop"].steam_version=x86
steam["HELLDIVERS™ 2.desktop"].gamescope=0

SD card filesystem

#sd_card_filesystem

Prefer ext4 for a ROCKNIX-only Steam library card

/storage/games-external/roms/steam/steamapps/compatdata/<appid>/pfx
/storage/games-external/roms/steam/steamapps/shadercache/<appid>

If an SD card is dedicated to ROCKNIX or another Linux setup, ext4 is usually safer than exFAT for Steam games that use Proton. Proton's Wine prefix behaves like a small Windows install stored inside Linux folders, and it can depend on Linux-style metadata such as ownership, permissions, executable bits, and symbolic links.

exFAT is convenient for cards shared with Android, Windows, or another handheld OS, but it does not provide the same native Linux filesystem behavior. That mismatch can show up as odd prefix behavior: first-run setup repeating, launchers failing to save config, missing files inside the prefix, or a game working from internal storage but acting strange from the card.

Caution: Formatting erases the card. Use ext4 only when the card does not need to be shared with Android, Windows, or another non-Linux device.

Example: HELLDIVERS 2

/storage/games-external/roms/steam/steamapps/compatdata/553850/pfx
/storage/games-external/roms/steam/steamapps/shadercache/553850

Compatdata cleanup

#compatdata_cleanup

Let Steam rebuild stale per-game data

/storage/.local/share/Steam/steamapps/compatdata/<appid>
/storage/.local/share/Steam/steamapps/shadercache/<appid>

Switching Steam x86/ARM, Proton major versions, Steam Native, or custom tools can leave a game using old compatibility prefix or shader cache data. If a game only starts failing after those runtime changes, moving aside or removing the per-game folders lets Steam generate clean ones on the next launch.

Caution: Back up first and close Steam before cleanup. These folders can include per-game Proton prefix state, saves stored inside the prefix, and compiled shader data.

Example: HELLDIVERS 2

/storage/.local/share/Steam/steamapps/compatdata/553850
/storage/.local/share/Steam/steamapps/shadercache/553850

Runtime version

#runtime_version

Proton version is stored in Steam's compat tool mapping

/storage/.local/share/Steam/config/config.vdf
"CompatToolMapping"
{
  "<appid>"
  {
    "name"    "<compat-tool>"
    "config"  ""
    "priority"  "250"
  }
}

Preferred path: Steam game Properties, Compatibility, force a compatibility tool, then choose the Proton or Steam Native runtime. The name value is the selected compatibility tool id for the game.

For official Steam Proton tools, the Steam Linux Runtime is not listed in compatibilitytool.vdf. Follow the tool's toolmanifest.vdf instead: require_tool_appid gives the runtime appid, appmanifest_<appid>.acf gives the installed folder, and the runtime folder's toolmanifest.vdf confirms the runtime layer.

/storage/.local/share/Steam/steamapps/common/Proton - Experimental/toolmanifest.vdf
/storage/.local/share/Steam/steamapps/common/Proton Hotfix/toolmanifest.vdf
/storage/.local/share/Steam/steamapps/common/Proton 11.0/toolmanifest.vdf
/storage/.local/share/Steam/steamapps/common/Proton 10.0/toolmanifest.vdf
"require_tool_appid"  "<runtime-appid>"

Runtime appid map

4183110 -> Steam Linux Runtime 4.0
          /storage/.local/share/Steam/steamapps/common/SteamLinuxRuntime_4
4185400 -> Steam Linux Runtime 4.0 - Arm64
          /storage/.local/share/Steam/steamapps/common/SteamLinuxRuntime_4-arm64
1628350 -> Steam Linux Runtime 3.0 sniper
          /storage/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper
3810310 -> Steam Linux Runtime 3.0 sniper - Arm64
          /storage/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper-arm64

/storage/.local/share/Steam/steamapps/appmanifest_<runtime-appid>.acf
"name"        "<runtime name>"
"installdir"  "<runtime installdir>"

/storage/.local/share/Steam/steamapps/common/<runtime installdir>/toolmanifest.vdf
"compatmanager_layer_name"  "container-runtime"

"CompatToolMapping"
{
  "553850"
  {
    "name"    "proton_experimental"
    "config"  ""
    "priority"  "250"
  }
}

LaunchOptions file

#launch_options

Steam stores launch arguments in localconfig.vdf

/storage/.local/share/Steam/userdata/<user-id>/config/localconfig.vdf
"<appid>"
{
  "LaunchOptions"  "PROTON_LOG=1 %command%"
}

The Steam UI is the safest way to edit launch options. Keep %command% in the value so Steam still inserts the real game command. Change one launch option at a time and record the exact text.

The file view is useful for confirming what Steam saved for the app id.

"553850"
{
  "LaunchOptions"  "PROTON_LOG=1 %command%"
}

Enable Proton log

#proton_log

Proton logging is a Steam launch option

PROTON_LOG=1 %command%
/storage/steam-<appid>.log

Add the Proton log option in Steam game Properties, General, Launch Options. Proton writes the log after the game starts. Turn the option off again for normal play or performance testing.

Start with PROTON_LOG=1. Avoid broad WINEDEBUG unless you know what extra signal you need, because it can create huge logs and slow the game enough to change the result.

PROTON_LOG=1 %command%
/storage/steam-553850.log