Running the Pi 4 at 120hz?

[bomblord]

Anything preventing me from running the Pi 4 at 1080p 120hz? I assume the HDMI port can handle it since it can do 4k 60. Wanting to attempt to do black frame insertion and I have a TV that advertises a refresh rate of 120hz (2019 Vizio V series). What exactly would I need to do to get the Pi outputting that?

[trejan]

Is it actually accepting a 120Hz signal?

It'll probably need you to do a custom mode using hdmi_timings There is a 120Hz mode but it is 1080i.

[bomblord]

Is it actually accepting a 120Hz signal?

It'll probably need you to do a custom mode using hdmi_timings There is a 120Hz mode but it is 1080i.

Who knows, if it doesn't oh well. I've seen some workaround to force screens with the ability to run at 120hz to accept a 120hz signal (you need a Windows PC to do some of them).

[6by9]

Yes you can, although the current FKMS driver doesn't allow refresh rates above 85Hz as generally they give no gain but use more GPU time.
Alter/remove the limit at https://github.com/raspberrypi/linux/bl ... ms.c#L1013 if you really want 120Hz.

[Shikakiru]

hello

i have the same problem, i try to do evrithing here https://www.raspberrypi.org/documentati ... t/video.md

Mostly try different thinks : hdmi_safe=0/1 hdmi_group=1/0 hdmi_mode= 46/47

and of course i didn't forget to uncommente (after 10 or 20 time ^^)
and its working when the raspery pi 4 start (because my projector show the detection 1800 /120hz or 720 /120hz) but when raspbian start its not working it show another resolition 60hz

any idea? i don't understand how to unlock the 85hz? and i don't know if its really necessary unless its a raspbian driver... because its working befor raspbian start...

t

[peter_shaw]

just stumbled across the same problem.
i want to unlock 720p@120 hz. When setting the appropriate hdmi_group and mode, it works at the boot screen. as soon as the fkms driver gets activated, it changes back to 60 hz...