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Hacking the LG Monitor's EDID

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Re: Hacking the LG Monitor's EDID

#141

Post by kj800x »

Arnavion wrote: post #12

>Actually, the start of the function isn't that bad, but scroll down halfway and you'll find this: [...] Oh no, there's no way I'm going to be able to figure out all this byte manipulation in my head. I know the author says later that they don't do C development, but note that most of this code is just reading two consecutive bytes as a 16-bit integer, except for x[9] and x[17] where the high bit has a special meanin…

Now that you've mentioned that, that section is a lot more readable to me. Cheers! My C skills are inversely correlated to my body's uptime and it was probably around 1:30AM when I reached that part of the story

Re: Hacking the LG Monitor's EDID

#142

Post by kj800x »

dxld wrote: post #94

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 calc…

I genuinely take the baroque comment as a complement. There's many paths to a solution and this was a fun one that ended up working for me.

Thanks for the pointers for those programs. Someone else pointed out Kaitai Struct could help me do the hex editing which I'm planning on taking a look at later

Re: Hacking the LG Monitor's EDID

#143

Post by rampant_ai »

sotix wrote: post #88
rampant_ai wrote: post #40

LG's firmwares are pretty bad in my experience. I have two LG monitors and they both have weird quirks. On the first one (a 34" ultrawide), all of its inputs lose connection for a moment whenever it wakes from standby (including the USB ports, making them useless for external drives). This also has the effect of causing my computer to occasionally lock up on resume from hibernation unless I tap the power button on th…

> This also has the effect of causing my computer to occasionally lock up on resume from hibernation unless I tap the power button on the monitor before I wake the system. Wow you just off-handedly resolved an issue I’ve been dealing with for months on my Linux desktop. I lost an hour of Baldur’s Gate progress the other night after this happened after I hadn’t saved the game. Thank you! Your fix also resolves a simil…

> Wow you just off-handedly resolved an issue I’ve been dealing with for months

Awesome! Glad I could help.

> I wish there were a way to make the LG monitor work like my other one and not have to do that

Yeah unfortunately that would be on LG to release a firmware update. And from what I can tell, they'd rather you just buy the new revised model.

Re: Hacking the LG Monitor's EDID

#144

Post by thomastjeffery »

Dalewyn wrote: post #106
thomastjeffery wrote: post #57

Earlier quoted context omitted.

My favorite use case is Looking Glass. Want to play video games that only run in Windows, but don't want to leave Linux? You can run Windows in a virtual machine and "passthrough" your GPU's PCIe slot. The advantage is that Windows can get the full performance of your GPU. The disadvantage is that it took the whole GPU away from your Linux host, along with whatever display it's attached to. You can use a second GPU f…

Genuine question, but are multiple inputs on the monitor not a consideration for your scenario? Or are multiple inputs on a single monitor unsuitable for this purpose?

For Looking Glass, probably not: the guest OS will probably notice the monitor switching away from its connected input, and will stop drawing frames accordingly.

Re: Hacking the LG Monitor's EDID

#145

Post by thirdsun »

alin23 wrote: post #24

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…

> 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]

Are you sure this is still true? I had this problem for a very long time but it seems to have been fixed with a recent macOS update. It must have been one of the Ventura point releases.

Re: Hacking the LG Monitor's EDID

#146

Post by alin23 »

thirdsun wrote: post #145
alin23 wrote: post #24

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…

> 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] Are you sure this is still true? I had this problem for a very long time but it seems to have been fixed with a recent macOS update. It must have been one of the Ventura point releases.

Some people report having it fixed with 13.5.1. Some still have the problem because their monitors are missing the Alphanumeric Serial Number field.
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