I had similar issues with EDID on an old monitor. I pulled the cover off the back and found the I2C EEPROM that stored the EDID data. I soldered a jumper to disable the write protect on the EEPROM and was able to reprogram it using the Linux i2c-dev device.
Hacking the LG Monitor's EDID
81–90 of 146 posts
Re: Hacking the LG Monitor's EDID
#82Apparently there are $5-15 EDID "emulator" devices that are just an HDMI passthrough adapter with a fake EDID ROM that always reports common modes as 4K60/2K60/VGA. Apparent purpose is to get PS5 to work with quirky 4K TVs. A similar device called HDMI "dummy plug" allows GPU acceleration on quirky PCs without having a display, but the latter has no passthrough port at the back. If that's all the author needs, that m…
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…
I'll add that this setup works great, ran it for a good couple of years before finally dropping it (not for any looking glass reasons, eventually just didn't need it anymore with proton).
Also loved that it integrated so well into OBS directly to stream from!
Re: Hacking the LG Monitor's EDID
#83Earlier quoted context omitted.
Linux contains lots of code to work around a myriad of EDID quirks (and loads of other HW quirks), too: https://github.com/torvalds/linux/blob/master/drivers/gpu/dr... There certainly isn't any big philosophical point to make here, Linux doesn't take a hard stance of expecting correct HW. Ultimately this is a symptom of (1) bugs happen (here, at LG) and (2) Linux has a lower market share and therefore sees less testi…
> As mentioned earlier, it'd have applied to MSIE in 2005 as well. What's funny is, I was around in 2005 and had already adopted Firefox well before it was called Firefox. (I was also around for the release of IE 4, and spent half a day downloading it on our 56k modem on release day! Exciting times.) That's because the web is what I work on, and I am OK taking on buggy/beta stuff in the web domain because I learn use…
I think that's fine and a respectable choice. I think it's even OK to argue that Windows has a value prop as a paid product because MS spends more effort on HW-specific quirks handling, or arguments along those lines.
Still, I think it does matter what's technically going on and where the fault lies. I also think that just like browser diversity, OS diversity is a net positive for the enforcement of good standards that makes things work better for users overall.
For example, I'm willing to bet (and it's because I know cases of it :-) that many PC peripherals work better on Macs because Linux existing has made HW-manufacturers more standards-conscious than a Windows-only world would have, especially since so many HW/embedded engineers run it.
> I was wasting tremendous amounts of time and energy debugging stuff very like this monitor issue, and getting no transferable benefit out of it
You got me there - in my case it lead to a career of making cars, phones, game consoles and other stuff running Linux, so I guess the over-under on the direct utility shakes out a bit differently here :-)
That said, it's been a very long time since I've done any fiddling/debugging to make any HW work privately. Ironically, I've had a lot more issues making HW work correctly on the M1 Mac I also have, e.g. my (quirky) Bluetooth earbuds work a lot better on PipeWire than macOS ...
Re: Hacking the LG Monitor's EDID
#84I have two identical ASUS 1920x1200 monitors. The EDID on one of them got corrupted.
Dumped the EDID from the other monitor, put in a file in /usr/lib/firmware/edid, and added this to the grub command:
drm.edid_firmware=DVI-D-2:edid/asus-1920x1200.bin
Long Live Linux!
Re: Hacking the LG Monitor's EDID
#85Earlier quoted context omitted.
It would be nice to figure out why Windows and MacOS evidently didn't have the problem. If there's some additional probing that they're doing to catch the monitor out on its lies, Linux could do that too.
Mere speculation on my part, since I have no familiarity with the HDMI or DisplayPort protocols: 1. Windows/macOS might have a "quirks table" that hardcodes fixes for spec-violating devices. 2. Windows/macOS might ignore some reported EDID values and derive their own when they determine that the display behaves differently from what is reported (e.g. by recording response packet timings).
> (e.g. by recording response packet timings)
Even modern packetized display interfaces like DisplayPort are still fundamentally a one-way firehose for the pixel data. There's no provision for acknowledging or retransmitting data packets, and forward error correction is optional. The bidirectional sideband channels used for stuff like EDID are not timing-sensitive like the pixel data stream.
Re: Hacking the LG Monitor's EDID
#86Sounds exactly like the things that made me switch from Linux to MacOS 13 years ago. There's value in things just working and not having to learn about how my hardware actually works. Learned a lot though!
This has nothing to do with "Linux". The monitor is exposing a bad ID in its configuration block. Monitor says "I support 140Hz at 4k", so Linux (strictly the kernel framebuffer driver in use) says "OK then, that's the best one, give me that". And it doesn't work, because the Monitor lied. And the reason it works on Windows or (sometimes) MacOS is just that those systems have arbitrarily different default choices (e.…
I completely agree with you in principle. It's rarely an actual fault of anything in Linux. However the outside effect to me as a user is that I need to debug my monitor's EDID to get it to work correctly. Inconveniently for me (as much as I love digging into things like that) I really want to just plug in a conference room projector into my laptop and have other people already put in place out those workarounds for me sometimes.
Re: Hacking the LG Monitor's EDID
#87What's with LG in general? It seems they often have problems with EDIDs.
Re: Hacking the LG Monitor's EDID
#88LG'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 similar issue I have on the Mac side when using my work laptop. If I tap the keyboard to resume from sleep, my LG monitor wakes up but doesn’t display an image. I have to wait for it to go through the motions until it finally displays “no input” before tapping on my keyboard to make it display the lock screen. Meanwhile, my second monitor works from the get go.
I somehow never thought to hit the power button first. I wish there were a way to make the LG monitor work like my other one and not have to do that.
Re: Hacking the LG Monitor's EDID
#89Sounds exactly like the things that made me switch from Linux to MacOS 13 years ago. There's value in things just working and not having to learn about how my hardware actually works. Learned a lot though!
Funnily enough, stuff not working on my m1 over the past year or so is precisely why I stick with Ubuntu on my thinkpad for all of my tasks except the ones that require macos! I don't think I've ever needed to debug any of my thinkpads with integrated gpus.
Re: Hacking the LG Monitor's EDID
#90Apparently there are $5-15 EDID "emulator" devices that are just an HDMI passthrough adapter with a fake EDID ROM that always reports common modes as 4K60/2K60/VGA. Apparent purpose is to get PS5 to work with quirky 4K TVs. A similar device called HDMI "dummy plug" allows GPU acceleration on quirky PCs without having a display, but the latter has no passthrough port at the back. If that's all the author needs, that m…
These devices are also used among home theater enthusiasts as a hack to enable LLDV (Low Latency Dolby Vision) which causes the source device to perform tone mapping.
http://videoprocessor.org/lldv
https://www.avsforum.com/threads/alternative-devices-for-ena...
https://blog.semtech.com/demystifying-dolby-vision-for-pro-a...