Unable to force 1080p while using 4k TV (Even with config edits)

Rahuruk

As stated I cannot figure out how to stop the Pi 4 from defaulting to the TV's native 4k resolution, even when I've edited the config.txt file to have hdmi group set to 1 and hdmi mode set to 16 as documented here: https://www.raspberrypi.org/documentation/configuration/config-txt/video.md

Since this appears to be an issue with the EDID forcing 4k resolution I have also tried to use the hdmi_ignore_edid=0xa5000080 line, however this causes retropie to no longer boot.

I have also gone into retroarch settings and added in a forced resolution there and that also is doing nothing.

Also, strangly, when I go into raspi-config and attempt to change the resolution there it kicks me out of the menu exactly as shown by this person here: https://www.reddit.com/r/RetroPie/comments/hg9wl2/retropie_wont_let_me_change_the_resolution_it/

Never had this issue on Pi 3, and having spent all day on google it seems to only be an issue on the Pi 4. I am pulling my hair out trying to solve this and posting this here is my last resort. I have given up.

mitu

Try adding

   hdmi_max_pixel_freq=200000000

to your config.txt. What TV model are you using ?

Androx

I had issues with my 4k TV and pi4. Although my issues was to do with it not fitting the full screen of the TV properly, when forcing 1080P through hdmi_group=1

I fixed it by going with DMT HDMI mode rather than CEC.

So for 60hz 1080P:

hdmi_group=2
hdmi_mode=82

What makes no sense is it still seems to function as CEC. For example if I reboot my pi while my TV is off, or on another channel, the pi will turn the TV on and/or change my TV's source to the pi, which I thought was a feature of CEC.

I was also getting the issue with raspi-config immediately kicking me out of the resolution menu until I set the above config changes.

Rahuruk

@mitu Thanks for the reply, I have entered that into the config.txt and booted up unfortunately to the same 4k resolution.

My TV is the Samsung MU2690.

I am also using the Pi 4 4GB model with no overclocking and am using a fresh retropie image as of last night's troubleshooting.

@Androx I just got to work a little bit ago but once I get home I will try that out.

Another bit of interesting information is that the pi when booted up appears to take the config.txt HDMI group and mode edits I currently have during the first few seconds of the booting process, and then the screen goes black for about 2 seconds and comes back on in 4k resolution.

I will record this event when I get home in a few hours to show it exactly.

YFZdude

Which HDMI port on the Pi 4 are you using?

It was my impression that some of these settings only affect the primary port unless you change the syntax.

Rahuruk

@YFZdude Yeah I have used both ports for the troubleshooting I've done so far, though the last couple edit attempts I've made I haven't so thanks for the reminder.

YFZdude

@Rahuruk Have you by chance tried the info below? This is from the same page you linked and looks like it could help when the Pi seems to ignore the group and mode settings.

hdmi_force_mode

Setting to 1 will remove all other modes except the ones specified by hdmi_mode and hdmi_group from the internal list, meaning they will not appear in any enumerated lists of modes. This option may help if a display seems to be ignoring the hdmi_mode and hdmi_group settings.

This could be a bit wild as I could see how it might make the display blank out and you may not be able to tell if it booted. Good if you can SSH into the Pi so you can shut down or edit the config file remotely.

Or there is this as well.

Which values are valid for my monitor?

Your HDMI monitor may only support a limited set of formats. To find out which formats are supported, use the following method:

Set the output format to VGA 60Hz (hdmi_group=1 and hdmi_mode=1) and boot up your Raspberry Pi
Enter the following command to give a list of CEA-supported modes: /opt/vc/bin/tvservice -m CEA
Enter the following command to give a list of DMT-supported modes: /opt/vc/bin/tvservice -m DMT
Enter the following command to show your current state: /opt/vc/bin/tvservice -s
Enter the following commands to dump more detailed information from your monitor:
/opt/vc/bin/tvservice -d edid.dat; /opt/vc/bin/edidparser edid.dat

The edid.dat should also be provided when troubleshooting problems with the default HDMI mode.

mitu

@Rahuruk said in Unable to force 1080p while using 4k TV (Even with config edits):

@mitu Thanks for the reply, I have entered that into the config.txt and booted up unfortunately to the same 4k resolution.
My TV is the Samsung MU2690.

Try with with

hdmi_max_pixel_freq:0=200000000
hdmi_max_pixel_freq:1=200000000

As @YFZdude mentioned, try running the tvservice commands and post the output.

Rahuruk

@YFZdude Alright man you are the winner, I had been doing config edits all day yesterday and tried both HDMI-D ports during those edits, and at some point at the end of the night when I did the hdmi_group 1 and hdmi_mode 16 edits I did not test the cord in the primary hdmi-d slot as I had thought.
It figures the one edit I added in that actually works is the one I stopped testing both slots on.

I have the pi 4 in a case so remembering which slot was the primary was my user error.
What a nightmarish night for something so simple, thanks again to everyone in here that helped out. It runs in 1080p now.

Edit: The resolution to the problem was having the hdmi cord plugged into the primary slot (nearest the usb hub) on the pi 4. User error.