edid.ksy VS cvt_modeline_calculator_12

An EDID override like this would be helpful for macOS as well, where the monitors swapping around after standby is a real annoyance [0] [1]

EDID rewrites are 99% of the time blocked by the monitor firmware: https://notes.alinpanaitiu.com/Decoding-monitor-EDID-on-macO...

By the way, one helpful tool that helped me navigate the EDID dump was Kaitai Struct [2]. It shows a side by side view with the hex view and the EDID structure, and it highlights the hex values in real time as you navigate the structure. Unfortunately [3] it doesn't support the extension blocks that the author needs.

[0] https://notes.alinpanaitiu.com/Weird-monitor-bugs

[1] https://forums.macrumors.com/threads/external-displays-swapp...

[2] https://kaitai.io/

[3] https://github.com/kaitai-io/edid.ksy

OP's approach looks cool but a bit baroque. I'm also hacking around EDID issues and it turns out there's a nice GUI program to decode and (lightly) patch it: https://packages.debian.org/unstable/utils/wxedid

I have to do more involved full EDID reconstruction surgery tho since I need to add DTD entries rather than just change existing ones. So I'm looking at [edid-generator] together with [cvt12]. The latter can calculate xrandr modelines for VESA standard timings that all seem to work with my TV. It adds an option for NTSC timing over regular cvt which is already in Debian.

[cvt12]: https://github.com/kevinlekiller/cvt_modeline_calculator_12

4) On Xorg, a custom resolution is represented using a "Modeline", which can be manually calculated, or generated using a utility like cvt. There's also a modified version with more advanced options. Then the modeline can be temporarily added using xrandr, or permanently added using /etc/X11/xorg.conf. Though in my experience, the Nvidia driver is a bit picky about adding modelines sometimes, it seems to be more accepting if you add them in xorg.conf instead of xrandr, and also if you add settings documented here to xorg.conf to disable some forms of mode validation.

Instead of using cvt or gtf, I used cvt12 to get get my Modeline. With cvt12, I was able to get a refresh rate of 160. It is 10 frames lower than my monitor's max, but I'm still happy with this solution.

If you haven't jumped ship to Wayland yet, maybe try using the same custom modeline for both screens? IIRC, you generate the modeline with a cvt calculator that supports reduced blanking v2, and then use it with xrandr --newmode , xrandr --addmode , xrandr --output --mode . Those 3 commands will need to be autorun on login, or possibly you could put the modeline in an xorg.conf.d snippet.

Build this from source: https://github.com/kevinlekiller/cvt_modeline_calculator_12

As to how I got the "magic" numbers in the first command? It was done via this program: https://github.com/kevinlekiller/cvt_modeline_calculator_12. I ran it like this:

Then you use the cvt tool (https://github.com/kevinlekiller/cvt_modeline_calculator_12) to calculate a new modeline for your monitor (I'm assuming by "custom" refresh rate, you want to overclock your monitor)