edid-generator

Hackerswork to generate an EDID binary file from given Xorg Modelines

An extension of the awesome work provided in the Linux kernel documentation (in docs/EDID).

Simplifies the process greatly by allowing you to use a standard modeline as well as automatically calculating the CRC and applying it to the resulting image.

Requirements

sudo apt install zsh edid-decode automake

Usage

If you don't have a <mode>.S prepared yet, generate one using a file containing Xorg Modelines. Lines that do not contain modelines are ignored, so you can just read right from xorg.conf.

./modeline2edid /etc/X11/xorg.conf

You can also just read from stdin the way you'd expect:

./modeline2edid
# or explicitly:
./modeline2edid -

After this creates your <name>.S files for each modeline it encounters, simply make:

make

The end result, providing all goes well, is a glorious EDID bin image for each mode you gave to it. A <name>.S file is templated, and then make is invoked to compile it into <name>.bin. It's actually compiled twice; once with an invalid CRC in order to generate said CRC to enter it into the template, after which we recompile, hence glorious bins.

NOTE: If you use a ratio other than 16:9, you'll need to specify it at the end of the modeline.as ratio=4:3. Ratios are hard defined in edid.S, so if you are trying to do something non-standard you'll need to add it.

Why?

Many monitors and TVs (both high and low end) provide invalid EDID data. After dealing with this for years, I wanted to automate this process.

The final straw was when I bought a cheap Sceptre 4K tv at a rather affordable ~$225 and ran into a long series of hurdles to get it to operate as expected at 3840x2160@60. After doing this enough times, I had to automate it or I was going to go crazy.

I used this to quickly iterate while troubleshhooting, finally it's all working from KMS all the way down to X!

(Via drm_kms_helper.edid_firmware=DP-1:edid/blah.bin if you're interested. I'm using radeon + intel, with nvidia you have to specify it in xorg.conf/xorg.conf.d as they don't yet support KMS for the fb console yet; their beta drivers, 367 at the time of writing, only support using KMS for the xorg server.)

Sometimes I hate being such a perfectionist. Keep in mind this project was made in a couple hours, I certainly didn't attempt to polish it in the least ;)