Raspberry Pi Forums

Hello,

I have a raspberry pi 4B which I am unable to set to my monitors native resolution of 1920x1080p at 75Hz. Resolutions available to me are 1024x768
800x600
848x480
640x480

This problem is present on every operating system I have tried (Raspian, Manjaro, Ubuntu). If I check the tvservice -m it says that my monitor is default 1280x720 at 75Hz, and 1920x1080 must run at 150Hz, twice the highest possible Hz of my monitor! If I select this mode, after it boots, my monitor tells me the refresh rate is not supported (which it obviously isn't.)

I know that the board and the monitor are able to "talk" to each other at 1080p, because when I made some changes in config.txt, the rainbow flash and the four raspberries were at the correct size, position and resolution for a 1080p monitor, but it doesn't work for the desktop.

I can use Raspberry Pi 3B+ with no problem. I also have a second Raspberry Pi 4B which was having the same problem, but I managed somehow to fix it; unfortunately I don't remember how, and I wiped the card to run open media vault.

Can anyone please help me because I'm getting extremely frustrated.

The monitor is an Acer VG270 75Hz 1920x1080p, and the Pi is a 4GB 4B with the latest firmware. It is connected directly to the monitor with a single micro HDMI to HDMI cable, no adapters or anything. It is powered by a third party 5.1v USB-C power supply made specifically for the Pi 4B, and the low power indicator has not once shown. The problem is there regardless of which micro-HDMI out port I use on the Pi, and I've tried running it through a receiver to the monitor (because the receiver would give the Pi different information about the connected device and runs at 60Hz) and a splitter, which did nothing to help.

I am tearing my hair out, all suggestions are welcome no matter how obvious they seem, I will try anything, even if it's just commands for you to get more information about my setup but please keep in mind that the hardware is almost certainly not faulty, because the boot screen was able to be displayed in proper 1080p resolution, and I had the issue with another Pi 4B but I don't remember how I fixed it, it is running OMV now (and the command line for OMV was correctly displayed in 1080p resolution during setup).

Many thanks!

EDIT: For simplicity, I will do a clean install of Raspian Buster with desktop, and run update and upgrade, but make no other changes.

sounds like you need to work out a custom HDMI timing.

aBUGSworstnightmare wrote: ↑

Thu May 28, 2020 1:09 pm

sounds like you need to work out a custom HDMI timing.

Thanks for your response
Could you please tell me how? Or point me in the right direction? Do you know why this is a problem with the 4B and not 3B+?

This is the result of tvservice -m CEA:

Group CEA has 4 modes:
mode 4: 1280x720 @ 60Hz 16:9, clock:74MHz progressive
mode 16: 1920x1080 @ 60Hz 16:9, clock:148MHz progressive
mode 95: 3840x2160 @ 30Hz 16:9, clock:297MHz progressive
mode 97: 3840x2160 @ 60Hz 16:9, clock:594MHz progressive

The monitor's refresh rate is 75Hz, if I try to use mode 16 for the native resolution my monitor reports that the input is not supported.

EDIT: This is what tvservice -m CEA gives me on a Pi 3B+, on a fresh buster install with no changes made (and it displays correctly, albeit with overscan which I would turn off):

Group CEA has 11 modes:
mode 1: 640x480 @ 60Hz 4:3, clock:25MHz progressive
mode 2: 720x480 @ 60Hz 4:3, clock:27MHz progressive
mode 3: 720x480 @ 60Hz 16:9, clock:27MHz progressive
mode 4: 1280x720 @ 60Hz 16:9, clock:74MHz progressive
mode 5: 1920x1080 @ 60Hz 16:9, clock:74MHz interlaced
(prefer) mode 16: 1920x1080 @ 60Hz 16:9, clock:148MHz progressive
mode 17: 720x576 @ 50Hz 4:3, clock:27MHz progressive
mode 18: 720x576 @ 50Hz 16:9, clock:27MHz progressive
mode 19: 1280x720 @ 50Hz 16:9, clock:74MHz progressive
mode 20: 1920x1080 @ 50Hz 16:9, clock:74MHz interlaced
mode 31: 1920x1080 @ 50Hz 16:9, clock:148MHz progressive

Why should they be any different?

For anyone in the future that has the same problem as I described, here's how I fixed it:

1. Buy a new HDMI cable

..

That's it!



I actually bought a pack of two micro-HDMI to standard HDMI adapters from amazon because they were cheaper and I don't have much use for a cable that is only micro HDMI.

Couldn't be happier to use my new 8GB Pi at 1080 @ 75Hz for retro gaming!

Thanks for the suggestions and trying to help!