FPSLocker

An overlay that with SaltyNX allows to set custom display refresh rate and FPS in Nintendo Switch retail games.

Disclaimer: Tool is utilizing detection of graphics API to manipulate FPS and in special cases it requires using patches made per game for each version to get more than 30 FPS. You can find those patches HERE
Max supported yaml size is 32kB, though it can be expanded in next updates.

Requirements

Atmosphere CFW
My fork of SaltyNX, version 0.7.5+
Tesla environment: ovlloader + Tesla Menu

How to setup everything: HERE

Usage

Overlay runs in two modes:

When game is running

If game is supported by SaltyNX and you installed everything correctly, you will see menu where first line states NX-FPS plugin is running. Explanation of each line:

Interval Mode - it's used by NVN API to set limiter to either 30 FPS (2) or 60 FPS (1).
Custom FPS Target - it's used to lock game to certain FPS. If game is using engine proprietary FPS locks, it may not be able to unlock more than 30 FPS without additional patches.
Big number on the right - it shows how many frames have passed in last second for currently running game. This is to confirm that lock is working as expected.
Increase/Decrease FPS target - Change FPS Target by 5. Minimum is 15 FPS, max is 60 FPS. If FPS is set above 30 FPS, it sets interval mode to 1. Otherwise it sets interval to 2.
Disable custom FPS target - Removes FPS Target. Since we cannot predict what interval mode is expected at this point, it is in user's discretion to manipulate FPS to bring back correct interval before disabling FPS target.
Advanced settings - submenu which consists of:
- If game is using NVN
  - Window Sync Wait - this is dangerous setting that disabled can crash game, but in some can bring benefit of disabling double buffer vsync at the cost of small graphical glitches (check list of games compatible with this solution at the bottom of README). Use it with caution. It won't show if game is not using double buffer.
  - Set Buffering - if game is using any other buffering than double, this option will show that will allow you to force game to run at any other buffering that is not higher than original one (so f.e. you cannot change double buffer to triple buffer). Lowering buffer is recommended only for games that have near perfect performance at 30 or 60 FPS, but suffer from bad framepacing or big input lag. If you will force double buffer in games with uneven performance, FPS drops will be very severe. It can be applied only at boot of game, so after changing buffering you must save settings in FPSLocker and restart game.
    Explanation of Set/Active/Available Buffers:
    - Set - how many buffers were set by using nvnWindowSetNumActiveTextures. If game is not using it, it will be 0. It can be used by games to set lower buffer value than reserved space allows. If this is detected to be used and lower than Available Buffers, you can use "(force)" variant next to default option. Without (force) it will reset to default settings.
    - Active - How many buffers are actually used by game.
    - Available - How many buffers is actually provided to NVN. We can use this information to force games to utilize all buffers when they are not doing it.
- Convert config to patch file - if proper config file exists for this game and version, you will get an option to convert it to patch file that will be loaded when you will run this game next time. Patch is saved to SaltySD/plugins/FPSLocker/patches/*titleid_uppercase*/*buildid_uppercase*.bin
- Delete patch file - if proper config file exists for this game and version, you will get an option to delete patch file so it won't be loaded when you will run this game next time.
- Check/download config file - Checks in Warehouse repository if config for this game and version exists. If exists, it is downloaded and also checked if it's the same as the one on sdcard. If it's not, overlay will remove existing patch and config file, and user must manually convert new config to patch file. If config doesn't exist in repository for this game and version, you should get Err 404. 0x312 error means we got unexpected file from github. Any other error means that something is happening with your connection or github server.
Save settings - save profile for currently running game that will be loaded next time by plugin on boot automatically. Don't use it if you disabled Sync Wait and you didn't test it properly that it won't cause crash. Profile is saved in SaltySD/plugins/FPSLocker/*titleid_uppercase*.dat
Display settings - submenu available only for non OLED model users. Consists of:
- Increase refresh rate - change display refresh rate up to 60 Hz.
- Decrease refresh rate - change display refresh rate down to 40 Hz.
- Display Sync - When turned on, both options above are not available, display refresh rate is changed only when game is running, and matches refresh rate with FPS Target. In case if FPS Target is below 40 FPS, refresh rate is restored to 60 Hz.

When game is not running

You will have two submenus to choose from (if you are using OLED model, you will be redirected automatically to Games list):

Games list
It will list installed games (max 32) and as first option it's available "All" submenu.
Inside each one you will find two options:
- Delete settings - it will delete file created by "Save settings" option
- Delete patches - it will delete file created by "Convert config to patch file" option
Display settings - submenu available only for non OLED model users. Consists of:
- Increase refresh rate - change display refresh rate up to 60 Hz.
- Decrease refresh rate - change display refresh rate down to 40 Hz.
- Display Sync - change display refresh rate only when game is running, match refresh rate with FPS Target. In case if FPS Target is below 40 FPS, refresh rate is restored to 60 Hz.

Information about changing refresh rates

I want to use this space to clarify few things.

OLED screens were getting often issues with green tint and ghosting below 60 Hz. 45 Hz works for some people properly only above certain brightness. I have decided to block OLED model completely until somebody will find more reliable way to change refresh rate for those displays.

From all reports I got, only one LCD screen was getting issue with small flickering in left bottom corner when running at 40 Hz (they were using InnoLux P062CCA-AZ2, but there were other users who also got this display and had no issues at 40 Hz - me included). No other issues were found.

I have decided to limit down to 40 Hz since lower refresh rates not only were not beneficial to user, also this allows avoid certain risks with underclocking display too much.

LCD can be overclocked up to 70 Hz without immediately visible issues but I have leaved max at 60 Hz since I have decided that there are no visible benefits running display at 70 Hz which would justify tinkering with existing patches to patch games breaking above 60 FPS. From 75 Hz all users were reporting issues with glitchy image. OLED above 65 Hz was freezing and only way to got it back working again was lowering refresh rate to 65 Hz and lower.

This works only for builtin display, you cannot change refresh rate in docked mode. If Display Sync is turned off, custom refresh rate is not restored after sleep mode.

Changing refresh rate affects animations speed of OS and Tesla overlays, making them more sluggigsh at lower refresh rates.

Adding support for custom display refresh rate required changing how game configs are written, so you are advised to redownload all FPSLocker Warehouse configs if you want them to properly support custom refresh rates.

I am not taking any responsibility for damages occuring from changing refresh rate. Each time you will go to Display settings, you will be welcomed by prompt with warning that you - user - are taking full responsibility. You must choose Accept to go further.

Thanks

Thanks to ~WerWolv for creating Tesla environment, and ~cucholix + ~Monked for tests.

Sync Wait

In those games you can disable double buffer vsync by turning off Window Sync Wait in FPSLocker: