customresolution

README

customresolution

A CLI tool that creates custom EDID profiles for Linux. Generate custom screen resolutions and load them via the kernel's drm_kms_helper.edid_firmware parameter.

Installation

go install github.com/guillermo/customresolution@latest

Or build from source:

git clone https://github.com/guillermo/customresolution.git
cd customresolution
go build -o customresolution .

Usage

List Connected Displays

customresolution list

Shows all connected displays with their current EDID information:

DISPLAY        STATUS      RESOLUTION  NAME            MANUFACTURER
card1-DP-1     connected   2560x1440   Dell S2722QC    DEL
card1-HDMI-A-1 disconnected -           -               -
card1-eDP-1    connected   1920x1080   Internal        BOE

Generate Custom EDID

Create an EDID for a specific resolution:

customresolution generate --width 2560 --height 1440 --refresh 60 -o custom.bin

Or use a preset:

customresolution generate --preset ultrawide-1440 -o ultrawide.bin

Options:

• -W, --width - Horizontal resolution in pixels
• -H, --height - Vertical resolution in pixels
• -r, --refresh - Refresh rate in Hz (default: 60)
• -o, --output - Output filename
• -p, --preset - Use a preset resolution
• -n, --name - Custom monitor name in EDID

List Presets

customresolution presets

Available presets include:

Name	Resolution	Refresh	Description
1080p	1920x1080	60Hz	Full HD
1440p	2560x1440	60Hz	QHD
4k	3840x2160	60Hz	4K UHD
ultrawide-1080	2560x1080	60Hz	Ultrawide Full HD (21:9)
ultrawide-1440	3440x1440	60Hz	Ultrawide QHD (21:9)
superwide	5120x1440	60Hz	Super Ultrawide (32:9)
1080p144	1920x1080	144Hz	Full HD 144Hz
1440p144	2560x1440	144Hz	QHD 144Hz

Install EDID

Install the EDID binary to /lib/firmware/edid/ and get instructions:

sudo customresolution install custom.bin DP-1

This will:

1. Copy the EDID to /lib/firmware/edid/
2. Show the kernel parameter to add

Parse Existing EDID

Inspect an EDID file:

customresolution parse custom.bin
customresolution parse --hex custom.bin  # with hex dump

Kernel Configuration

After generating and installing an EDID, configure the kernel to use it:

GRUB (Permanent)

Edit /etc/default/grub:

GRUB_CMDLINE_LINUX="drm.edid_firmware=DP-1:edid/custom.bin"

Then run:

sudo update-grub
sudo reboot

Temporary (Until Reboot)

echo 'DP-1:edid/custom.bin' | sudo tee /sys/module/drm/parameters/edid_firmware

Multiple Displays

Separate multiple displays with commas:

GRUB_CMDLINE_LINUX="drm.edid_firmware=DP-1:edid/custom.bin,HDMI-A-1:edid/hdmi.bin"

Use Cases

• Force a specific resolution on displays that don't advertise it
• Override faulty EDID on cheap monitors/cables
• Create custom resolutions for retro gaming
• Test display drivers with specific timing parameters
• Work around scaling issues on HiDPI displays

How It Works

EDID (Extended Display Identification Data) is a data structure that displays send to graphics cards to describe their capabilities. This tool:

1. Parses existing EDID from /sys/class/drm/*/edid
2. Generates valid 128-byte EDID structures with CVT timing
3. Installs EDID to /lib/firmware/edid/ for kernel loading

The generated EDID includes:

• Detailed timing descriptor with calculated CVT timings
• Display range limits
• Monitor name and serial

Requirements

• Linux with DRM/KMS drivers
• Go 1.21+ (for building)
• Root access (for install command)

License

MIT