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Hardware Setup:

  • Raspberry Pi 5 (8GB RAM)
  • Monitor: Gigabyte M28U
  • HDMI Cable: Certified HDMI 2.0
  • OS: Raspberry Pi OS Bookworm (fully updated, kernel 6.6.20)

Issue:
After configuring /boot/firmware/config.txt and validating EDID support for 4K@60Hz, the Pi 5 still outputs 3840x2160@30Hz instead of 60Hz.

Steps Already Taken:

  1. Forced 4K@60Hz in config.txt: 
    hdmi_enable_4kp60=1
hdmi_group=1
hdmi_mode=97
hdmi_force_mode=1
hdmi_drive=2
config_hdmi_boost=7
  2. EDID Validation:
    • Monitor’s EDID explicitly lists 3840x2160@60Hz (DTD 1 and VIC 97).
    • EDID override attempted via dtoverlay=edid,edid=... with no success.
  3. Firmware/OS Updates:
    • Updated bootloader (rpi-eeprom-update -a) and packages.
    • Tested LibreELEC nightly builds (same issue).
  4. Cable/Port Checks:
    • Confirmed HDMI 0 port (Pi 5) and HDMI 2.1 port (M28U) are used.
    • Tested multiple certified HDMI 2.0/2.1 cables.

Diagnostic Outputs:

  1. modetest Output (No 60Hz Mode): 
    #0 3840x2160 30.00 3840 4016 4104 4400 2160 2168 2178 2250 297000 flags: phsync, pvsync; type: driver
  2. EDID Excerpt (via edid-decode): 
    DTD 1: 3840x2160 60.000000 Hz (594.000 MHz)  
VIC 97: 3840x2160 60.000000 Hz (HDMI 2.0)
malanga
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1 Answers1

0

You should do an upgrade!

The 28 October 2024 upgrade introduced an improved compositor labwc which is recommended for all models running Bookworm.

According to the Raspberry Pi Ltd. documentation "5-series devices support up to two displays at 4K resolution at a 60hz refresh rate with no additional configuration". It is unclear if this requires labwc which I assume you have enabled (if it isn't default for a fresh install).

Milliways
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