How to setting 60 fps for slint ?

[fluolite]

Hi, Here I come back again!

I try to run a slint app with below slint environment variable.
But slint fps bar always show 30 fps
How can I use it correctly for 60 fps rendering.

# for debug
export SLINT_DEBUG_PERFORMANCE=refresh_full_speed,overlay

# for backend
export SLINT_BACKEND=linuxkms-femtovg
or
export SLINT_BACKEND=linuxkms-skia-opengl
or 
export SLINT_BACKEND=linuxkms-skia-software

# for output
 #get connector from 'export SLINT_DRM_OUTPUT=list   '
export SLINT_DRM_OUTPUT=HDMI-A-1

# get mode index from 'export SLINT_DRM_MODE=list'
export SLINT_DRM_MODE=1

In addition, slint debug log can not found tracing current select refresh rate.
It would be better with the value of refresh rate

Using Skia Software renderer
Rendering at 1920x1080
Rendering at 1920x1080@60   #add refresh rate?
...

Here is my device info from slint's output.

DRM Output List Requested:
HDMI-A-1 (connected: true)
DSI-1 (connected: true)

DRM Mode List Requested:
Index: 0 Width: 1920 Height: 1080 Refresh Rate: 60
Index: 1 Width: 1920 Height: 1080 Refresh Rate: 60
Index: 2 Width: 1600 Height: 900 Refresh Rate: 60
Index: 3 Width: 1280 Height: 1024 Refresh Rate: 75
Index: 4 Width: 1280 Height: 1024 Refresh Rate: 60
Index: 5 Width: 1152 Height: 864 Refresh Rate: 75
Index: 6 Width: 1280 Height: 720 Refresh Rate: 60
Index: 7 Width: 1280 Height: 720 Refresh Rate: 60
Index: 8 Width: 1024 Height: 768 Refresh Rate: 75
Index: 9 Width: 1024 Height: 768 Refresh Rate: 60
Index: 10 Width: 800 Height: 600 Refresh Rate: 75
Index: 11 Width: 800 Height: 600 Refresh Rate: 60
Index: 12 Width: 720 Height: 480 Refresh Rate: 60
Index: 13 Width: 720 Height: 480 Refresh Rate: 60
Index: 14 Width: 640 Height: 480 Refresh Rate: 75
Index: 15 Width: 640 Height: 480 Refresh Rate: 60
Index: 16 Width: 640 Height: 480 Refresh Rate: 60
Index: 17 Width: 720 Height: 400 Refresh Rate: 70

[tronical]

What you're doing looks correct - the way you're selecting the mode. I don't know why you're only seeing 30FPS. Is it possible that your screen can't actually drive the resolution at 60 Hertz? What's the CPU usage? Do you get 60 FPS in wayland?

[fluolite]

It can run 60 FPS with QtQml in eglfs backend.