Help with Custom EDID

Linux@lemmy.ml – 26 points – 4 months ago

Edit: Solved, while changing EDID make sure to remove the old module first and reinstall it with the new EDID

I have a faulty DP to HDMI adapter, that unfortunately never seems to parse the EDID data, so while connecting to a TV I used this guide and a 1920x1080.bin file from the internet and it worked, but unfortunately I was unable to use the TV speakers(I guessed the EDID file didn't specify that the device had audio out)

Using a separate pc I extracted my TVs EDID.bin file and repeated the steps but unfortunately, it just doesn't work, its stuck on the old 1920x1080.bin(I can tell because it shows up as 'Linux Foundation 23'') The issue persists even after I delete the old .bin file from /usr/lib/firmware/edid

I am using wayland

System info:

OS: Fedora Linux 40 (Workstation Editi 
Host: TECRA R940 PT439V-03U02WAR 
Kernel: 6.8.11-300.fc40.x86_64 
Uptime: 29 mins 
Packages: 2209 (rpm), 32 (flatpak) 
Shell: bash 5.2.26 
Resolution: 1920x1080 
DE: GNOME 46.2 
WM: Mutter 
WM Theme: Adwaita 
Theme: Adwaita [GTK2/3] 
Icons: Adwaita [GTK2/3] 
Terminal: gnome-terminal 
CPU: Intel i7-3540M (4) @ 3.700GHz 
GPU: AMD ATI Radeon HD 7550M/7570M/765 
Memory: 1998MiB / 7879MiB

Dmesg -H

[Jun20 22:26] Linux version 6.8.11-300.fc40.x86_64 (mockbuild@f09cc32e12c24ed6a1a66c2a2e9f1728) (gcc (GCC) 14.1.1 20240522 (Red Hat 14.1.1-4), GNU ld version 2.41-37.fc40) #1 SMP PREEMPT_DYNAMIC Mon May 27 14:53:33 UTC 2024
[  +0.000000] Command line: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-6.8.11-300.fc40.x86_64 root=UUID=XXXXX ro rootflags=subvol=root rhgb quiet drm.edid_firmware=DP-2:edid/sony.bin

Any help is appreciated

Is edid/sony.bin your new EDID? Does it revert back if you remove drm.edid_firmware all together?

Also, do you mind sharing your EDID? I had to edit mine to get VRR to work, so maybe there's something invalid in yours. It does contain serial numbers though if that's a problem.

Is edid/sony.bin your new EDID?

Yes

your new EDID? Does it revert back if you remove drm.edid_firmware all together?

how do i do that?

Here is the EDID file I decoded using edid-deode

how do i do that?

Probably by editing your GRUB config or whatever bootloader you're using.

Here is the EDID

Thanks, that should be enough I'll have a look when I'm free. Also something like get-edid > monitor.bin would probably be easier for me though.

Edit: I've had a look, I can't see any issues. Both checksums validate correctly and it advertises audio support. As you've probably seen in edid-decode, I'd expect it to show as 'SONY TV' (or at least for KDE 'Sony SONY TV' I believe).

Thank you, removing the module and adding it again fixed the issue, for future reference is there an easier more seamless way to go about it?

To me that does sound like your initramfs just needed recreating, since un/installing a module will do that usually.

What did you have to change for VRR? I’m also having an issue where I need to force the EDID and haven’t been able to get VRR

I wrote a guide here: stevetech.me/posts/force-enable-vrr-edid

But it was mostly just changing random things and hoping for the best, so YMMV. I hope it helps!

Thank you!

Did you rebuild your initramfs? The files needs to be available pretty early during boot and that's probably why it still seems the old one.

I just did using the dracut command, it didn't change anything, is there another more simpler way to go about this without risking messing up my system?

Dracut is the correct way to do this on Fedora so nothing else needs to be done. Then I'm not sure why it's not taking it.

the last time i tried doing something similar was with a plasma 1080i tv (yes that long ago) connected via hdmi to component adapter and i eventually learned that the nvidia driver will overwrite everything in favor of it's own detection method, thus ignoring the custom edid i provided; perhaps the ati driver your using does something similar?

i would have tried switching to one of the open source drivers but the tv died and it's replacement had hdmi ports and the problem went away

No before i passed the custom EDID it showed up as "Unknown display" and letter-boxed the entire display, limiting my resolution to 640x480 and 1366x768

Display port does not have audio

Does DisplayPort also support audio?

Yes, DisplayPort supports multi-channel audio and many advanced audio features. DisplayPort to HDMI adapters also include the ability to support HDMI audio.

https://www.displayport.org/faq/

None of my monitors (which are all DisplayPort) have audio, but one appears in the audio settings, so I'd say DisplayPort itself does support audio.