[GH-ISSUE #218] [BUG] DualSense controller causes massive FPS drop (45-55 FPS vs 120+ FPS) if split_lock_detect enabled #147

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opened 2026-10-15 12:57:08 +00:00 by bsakaguchi · 3 comments

bsakaguchi commented

2026-10-15 12:57:08 +00:00

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Originally created by @Gylfkxjyjdll on GitHub (Jun 28, 2025).
Original GitHub issue: https://github.com/games-on-whales/wolf/issues/218

When connecting a DualSense controller via USB or Bluetooth, all games experience severe framerate drops (from 120+ FPS down to 45-55 FPS). This persists across multiple titles but does not occur with other controllers. Performance immediately recovers upon disconnecting the controller or relaunching games without the controller connected.

System & Environment:
OS: Linux Debian 12.11
Kernel: Linux 6.14.5-1-bpo12-pve

Steps to Reproduce:
Launch a game
Ensure stable framerate without controller
Connect DualSense controller via USB or Bluetooth (moonlight)
Observe immediate FPS drop to 45–55 FPS.
Disconnect controller → FPS returns to normal.

Expected Behavior:
Steady FPS (60+) regardless of DualSense connection, matching behavior of other controllers.

Workaround:
Adding split_lock=off to kernel parameters resolves the issue.

my grub parameter atm: GRUB_CMDLINE_LINUX_DEFAULT="nouveau.blacklist=1 quiet nvidia-drm.modeset=1 intel_iommu=on systemd.unified_cgroup_hierarchy=false split_lock_detect=off"

Originally created by @Gylfkxjyjdll on GitHub (Jun 28, 2025). Original GitHub issue: https://github.com/games-on-whales/wolf/issues/218 When connecting a DualSense controller via USB or Bluetooth, all games experience severe framerate drops (from 120+ FPS down to 45-55 FPS). This persists across multiple titles but does not occur with other controllers. Performance immediately recovers upon disconnecting the controller or relaunching games without the controller connected. **System & Environment:** OS: Linux Debian 12.11 Kernel: Linux 6.14.5-1-bpo12-pve **Steps to Reproduce:** Launch a game Ensure stable framerate without controller Connect DualSense controller via USB or Bluetooth (moonlight) Observe immediate FPS drop to 45–55 FPS. Disconnect controller → FPS returns to normal. **Expected Behavior:** Steady FPS (60+) regardless of DualSense connection, matching behavior of other controllers. **Workaround:** Adding split_lock=off to kernel parameters resolves the issue. my grub parameter atm: `GRUB_CMDLINE_LINUX_DEFAULT="nouveau.blacklist=1 quiet nvidia-drm.modeset=1 intel_iommu=on systemd.unified_cgroup_hierarchy=false split_lock_detect=off" `

bsakaguchi closed this issue

2026-10-15 12:57:08 +00:00

bsakaguchi commented

2026-10-15 12:57:09 +00:00

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@ABeltramo commented on GitHub (Jun 28, 2025):

Thanks for the details, after a quick search I've found this article and https://github.com/ValveSoftware/steam-for-linux/issues/8003

Sounds like something that we should be able to address user land in Inputtino, possibly something silly with how we use uhid..

@ABeltramo commented on GitHub (Jun 28, 2025): Thanks for the details, after a quick search I've found [this article](https://www.phoronix.com/news/Linux-Splitlock-Hurts-Gaming) and https://github.com/ValveSoftware/steam-for-linux/issues/8003 Sounds like something that we should be able to address user land in Inputtino, possibly something silly with how we use uhid..

bsakaguchi commented

2026-10-15 12:57:09 +00:00

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@Strykar commented on GitHub (Jul 1, 2025):

The old split_lock_detect is now a sysctl tunable named split_lock_mitigate since kernel 6.2 - https://wiki.archlinux.org/title/Steam/Game-specific_troubleshooting#Split_lock_detection_/_mitigation

@Strykar commented on GitHub (Jul 1, 2025): The old `split_lock_detect` is now a sysctl tunable named `split_lock_mitigate` since kernel 6.2 - https://wiki.archlinux.org/title/Steam/Game-specific_troubleshooting#Split_lock_detection_/_mitigation

bsakaguchi commented

2026-10-15 12:57:09 +00:00

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@Gylfkxjyjdll commented on GitHub (Sep 19, 2025):

I am uncertain if this issue has been resolved, but I have tested this with my DualSense controller again and have not experienced this significant FPS drop. This issue can be closed.

@Gylfkxjyjdll commented on GitHub (Sep 19, 2025): I am uncertain if this issue has been resolved, but I have tested this with my DualSense controller again and have not experienced this significant FPS drop. This issue can be closed.