LG's $1,300 5K monitor foiled by Wi-Fi: Screens go blank near hotspots LG's space-age monitors are suffering from an engineering flaw that causes the screen to become unusable when placed too close to a Wi-Fi hotspot. Owners of the top-end displays writing on Apple's reviews page say they have found that, when placed within two metres of a router or wireless access point, an UltraFine 5K monitor …
> "can even cause the connected Macs to freeze, requiring a restart." (? what's freezing here: the screen, the Mac, both?)
At a guess, it could be something like: the monitor goes faulty and repeatedly attaches and detaches from the display output on the Mac's video card; the Mac has to change the window manager & video card state when a monitor is attached or detached; the rapid toggling tickles a bug in the video driver or window manager, leading it to freeze; and you don't normally experience that bug because it's not normal to be able to repeatedly plug and unplug a monitor that quickly without a hardware fault.
Or maybe when the monitor's bugged it does something amusing like sending totally bogus EDID information that tickles a bug somewhere. "I have a width of -3200 pixels and I want to be driven at 4MHz" or something equally silly.
Given the complete uselessness of faulty hardware, bugs which only occur when you have faulty hardware plugged in aren't top of the priority list to fix. It's pretty reasonable that a problem like that could be left lying around for years.
I don't know how screen locking works on MacOS, but if it's as horribly stupid as X then a bug that would let you crash the foreground application would let you bypass the screen lock. So a bug that lets you do that by plugging in various forms of broken hardware would be security critical.
No idea if that applies here though as only hangs are mentioned, but it could very well be a sign the relevant code should be looked over.
"It is also fun than Macs freeze, as they obviously also did not test for interference."
You win the prize for random conclusion of the day. If Macs didn't test for interference they would likely also be subject to freezes and restarts when close to a router regardless of whether they're connected to LG's monitor or not.
As the poster above eloquently articulates, it's far more likely that the monitor is freezing, sending scrambled or corrupted information back down the signal line and tickling a bug in the video driver; but rather than state that that is 'obviously' the case, I would simply say that somebody needs to do a proper fault analysis on this and identify the root cause, rather than jumping to conclusions.
Amusingly* the immunity standards for IT equipment stop at 1 GHz for radiated immunity tests (which are harmonised in Europe and give a "presumption of conformity to the essential requirements").
That being said, even if your immunity tests do cover the Wi-Fi ranges, it'll generally be at 1V/m. If your Wi-Fi router is at full power, anything closer than ~4ft will be illuminated at more than 1 V/m. So there shouldn't strictly be any expectation of satisfactory operation.
* for some value of "amusing".
Or, if you read the article, you'd note that some users were able to mitigate by changing WiFi channel. It's possible that you could get a new neighbor who has a router blasting on the channel you're currently using. You might change you channel (or the airport could do it automagically if it's smart enough) and discover a problem - possibly after the warranty period expires.
Isn't any post-CRT monitor 'space age'? Heck, even the Sony Trinitron CRT was only released in 1968, after man in had been in space and not long before man set foot on the moon.
So, let's have some suggestions for a phrase to replace 'space-age'. Please leave them below!
Mars age?
Reusable rocket age?
Twitbook age?
"These are the days of miracle and wonder
This is a long distance call
The way the camera follows us in slo-mo
The way we look to a star
The way we look to a distant constellation
That's dying in a corner of the sky
These are the days of miracle and wonder
And don't cry baby, don't cry"
- From an album that begins with a description of an Improvised Explosive Device. It was a slow day...
Thanks for that tip!
I have an LG 34UM88C and it has exactly the same problem (I have my access point underneath my desk, directly beneath the monitor). If I shuffle in my chair, or as much as anyone goes by the room, it goes blank for a second or so.
It only happens on the HDMI connection, I noticed no problems with DisplayPort. Strangely, though, this is my second unit (the first one was replaced due to a panel fault) and I never noticed that on the first unit.
I remember in the days of CRT monitors when someone had their screen replaced because the picture used to wobble.
The new one started to do the same after a short time - they had put their electric fan back next to it again after moving it away for a while when the replacement was put in.
Doh!
As has been pointed out, a WiFi hotspot close to the monitor will be subjecting it to RF fields of a frequency and intensity outside the requirements of the present EMI immunity standards. Therefore unless the design specifications explicitly stated that it must be capable of operating next to a WiFi router, it is not the fault of the design engineer. Nor would I expect any testing process to include every conceivable mix of equipment that the device might be used with. This is the reason why mobile phones and other RF emitting devices are not permitted to be used on an aircraft (nowadays relaxed to be only during critical flight phases). Not because anyone believes that they WILL interfere with aircraft systems, but because the aircraft systems have not been tested or certified to operate with a mix of strong RF fields at random positions and frequencies within the aircraft, and so MIGHT be affected.
You can however bet your socks on the fact that not only LG but many other manufacturers will be adding the requirement to their design specs from now on.
Meanwhile the solution is pretty simple - move the WiFi hotspot. You'll probably even get better WiFi coverage when it's not being blocked by a large monitor ...
IEC-61000-4-3 2006 [...]
That's merely a basic standard, containing the test method. It doesn't require testing to be undertaken over the entire frequency range. The product standard for IT equipment is CISPR 24, which calls up IEC 61000-4-3, but only specifies its use up to 1 GHz.
And yes, I am an EMC engineer.
I've had to explain to an elderly fellow that the reason his laptop was utterly unreliable had to do with the fact that it sat on top of the generator housing for the log splitter. (I've heard about efficiencies etc, but it was a wacky setup). There was less than 1/4" of steel and less than 1' of clearance between the outer stator housing and the laptop. It would regularly mangle files, fail to boot, require a complete rebuild. Very likely didn't help that used power from the same source. It was the third complete rebuild I asked *exactly* where he was using it.
That said, that generator put out a *hell* of a lot more RF interference than anything folks are going to have hanging around their house making wifi.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2024
