[HN Gopher] Weird monitor bugs people sent me in the last 5 years
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Weird monitor bugs people sent me in the last 5 years
Author : alin23
Score : 273 points
Date : 2022-08-28 16:31 UTC (6 hours ago)
(HTM) web link (notes.alinpanaitiu.com)
(TXT) w3m dump (notes.alinpanaitiu.com)
| thewebcount wrote:
| I have a lot of respect for this developer's patience. Back when
| I was a solo developer, these types of issues were death by a
| thousand paper cuts. I didn't have the skills to deal with the
| amount of support and debugging these kinds of problems entail.
| And it's especially frustrating when the answer ends up being
| "It's due to how the manufacturer of this monitor just didn't
| properly implement the spec and there's nothing I can do to fix
| it." I can't imagine writing software where this is the norm! So
| kudos to the developer!
| alin23 wrote:
| Thank you! It is indeed a very frustrating kind of work.
|
| But still, a lot less frustrating than waking up at 6 AM for a
| Zoom call with an overseas company I'd be working. I prefer
| angry users of my own app over demanding (and often not knowing
| what exactly they demand) bosses.
| semireg wrote:
| I work on my own indie label printer app. Let me just tell
| ya, "label printers..."
|
| Sigh.
|
| I feel the pain. Stay strong.
| kayodelycaon wrote:
| Your software looks great! Is it generic enough to work on
| business cards?
| robk wrote:
| Just found your software. Looks neat! Buying a copy now for
| my zebra as soon as I'm on a desktop. Would have bought
| from mobile if you offered that!
| fossuser wrote:
| Nice overview of interesting bugs.
|
| I used to have a ton of issues with my MacBook Pro and
| thunderbolt monitor. These issues persisted through different
| MacBooks and monitors (we used the monitors at work and it was a
| work machine so I had a few).
|
| All of these issues finally went away after getting an M1
| machine. Maybe a coincidence but fewer monitor connection bugs
| was one of the noticeable changes for me.
|
| Based on the article it might also be because I switched to the
| apple pro display? Though I can't remember what happened first.
|
| Also off-topic, but this blog has beautiful style and typography.
| sroussey wrote:
| I found that after I updated the firmware of the monitors, they
| worked almost perfectly. And to make them actually work
| perfectly, I connect them on different sides on the MacBook Pro
| (intel version still). Took way too long to figure that out.
| alin23 wrote:
| Thanks, glad you like the styling ^_^
|
| And yes, it's very likely that most of your problems went away
| because you're using the Pro Display, as it has a much faster
| CPU than most monitor controllers on the market.
|
| Apple displays also support a proprietary USB protocol through
| which they can communicate with the Mac faster than through the
| DDC protocol which is still based on two-wire slowpoke I2C.
|
| That Apple Native protocol is also supported by Lunar for silky
| smooth brightness transitions, which is just not possible on
| DDC, unless the monitor has some kind of built-in fader.
| avian wrote:
| Maybe someone here can explain the following weird effect:
|
| My previous laptop (an HP EliteBook, the exact model escapes me
| at the moment) had an issue with Linux drivers where it would
| sometimes crash. When it crashed, the laptop's screen would
| quickly flash bright-dark-bright-dark... To my eye it looked like
| one garbage frame with mostly bright pixels and one frame with
| mostly dark pixels.
|
| Nothing weird so far - just a driver bug right? The weird thing
| was that when I rebooted the laptop after such a crash, the
| screen brightness would still slightly, but visibly blink in the
| same pattern, while the monitor was showing normal boot screen
| and later the login and desktop. The flashing would get less and
| less noticeable and kind of ring out by itself after a few
| minutes. After that the monitor was just working as normal.
|
| I can't think of a good reason why the monitor would keep
| blinking like that after a reboot. The best explanation I had was
| that perhaps some kind of adaptive algorithm for image
| postprocessing in the LCD driver had rolled off into an extreme
| and needed a while to get back to normal parameters. But it seems
| unlikely anything like that would have time constants in the
| range of minutes. The other possibility I thought about was that
| the blinking after a reboot was just a illusion created by my
| eyes, but I found that unlikely. I never saw anything similar.
| nyanpasu64 wrote:
| I managed to create the same effect by playing a video which
| displayed white and black frames in sequence, without a pre-
| existing monitor defect:
| https://www.youtube.com/watch?v=-CIzZv5al2E
|
| I think it's related to LCD inversion (http://www.lagom.nl/lcd-
| test/inversion.php#clickshow).
| alin23 wrote:
| Author here. My intuition says that's probably a faulty
| backlight panel.
|
| Not sure if you know that, but the liquid crystal that creates
| the image and colors is very dark by itself, so behind the
| crystal panel there's another panel filled with bright white
| LEDs to project the image into your eyes.
|
| Those LEDs can draw a lot of power and get hot, so they need
| proper passive cooling. In laptops that's usually achieved by
| gluing the LEDs to the lid and making the whole lid a massive
| heatsink (if it's a metal lid).
|
| It's possible that your backlight panel was overheating for
| some reason, or maybe it was just drawing more power than the
| source (old battery?) could provide. That would explain the
| continous blinking/ringing until the power/temperature
| stabilized, but it's really just a guess.
|
| It doesn't really sound like a software error anyway.
| echeese wrote:
| The URL of this page made me realize Firefox is happy to display
| spaces in URLs where Chrome will not.
| kiwijamo wrote:
| Does Firefox not replace spaces with %20? It does for me.
| Vecr wrote:
| It matters what your security settings for URL display are.
| There are attacks related to the URL bar (of course), so you
| can set Firefox to only display the raw urlencoded URL, or
| display emojis/non-ASCII characters visually. I guess there
| is theoretically ideograph attack mitigations in the second
| mode, but I don't trust it enough for the small benefit as an
| English language user.
| vxNsr wrote:
| As someone who is using display-switch[0] to imitate a hardware
| KVM switch in software I can say I've seen many of these issues
| in trying to debug the random issues that using ddc creates.
|
| Ddc is to http what your county clerk's website is to (current)
| healthcare.gov essentially. There's no standardization at all,
| it's maintained by 1000 different people who don't communicate
| and don't care how anyone else is doing it because only like
| 1/10000 people have heard of it and 1/100000 uses it.
|
| [0] https://github.com/haimgel/display-switch
| Karliss wrote:
| The first issue should be possible to deal with at OS level. Even
| if all the monitors send same serial number, OS should know in
| which port they are plugged in. Preferably things shouldn't swap
| if you swapped ports for your two monitors with properly unique
| serial numbers. But if the serial numbers are identical, ports
| seem like reasonable fallback since most people with multimonitor
| setups don't randomly unplug and plug them too often (except
| laptops).
| dt2m wrote:
| Thought the same thing. This must not be an issue on Windows
| either?
| fragmede wrote:
| You're assuming the ports enumerate the same when the system
| wakes back up.
| IshKebab wrote:
| No he isn't. He's assuming the wires are plugged into the
| same physical ports and the USB/Thunderbolt system makes that
| information available (it does).
| mhasbini wrote:
| A bit off topic: I'm facing an issue where a monitor works only
| when getting power (220v 60hz) from an outlet but not from an
| external power generator: ecoflow river pro (220v 60hz) as well.
|
| It's the only appliance that doesn't work. It turns on normally
| but stays black (I use it in mirror mode).
|
| Every hour or so it may show the correct content for a glance
| then it'll turn black.
|
| I suspect the power supply source is not the real reason, maybe
| there's something causing interference with the cable?
|
| I'm waiting to have a free weekend to check it out.
|
| Edit: I'll check if it's related to this issue:
| https://news.ycombinator.com/item?id=32631017
| alin23 wrote:
| It sounds very likely that this might be electromagnetic
| interference. The good part is that it's easy to troubleshoot,
| just move the generator (or the monitor, whichever is lighter)
| far away, like in another room or outside.
|
| You can also try a different, thicker cable, if you have one
| handy. The thicker cables are usually better shielded by having
| a sheath of tiny wires to catch that interference and conduct
| it to ground.
| alar44 wrote:
| My guess would be the power supply is putting out something
| closer to a square wave than a sine wave and the monitor power
| supply is unable to turn that into DC.
| jbverschoor wrote:
| My 4K LG monitor stutters and lags my M1 using the
| usb/DisplayPort cable while having audio enabled (stock cable)
|
| Easy fix is to set it to DP1.2 instead of 1.4
| alin23 wrote:
| Well that's a really odd bug :) I'll keep it in my notes for
| when the next user complains about Lunar making his monitor lag
| and stutter
| jbverschoor wrote:
| I think it's similar to the issues some people see with wifi
| not working. Because of the datarate which at that point
| matches the 2.4ghz 5ghz band.
| throwoutway wrote:
| > After standby or restart, the monitors get swapped by the OS,
| so moving the cursor to the left monitor will actually appear on
| the right monitor, and vice-versa.
|
| This happens to me all the time, and it's a small; annoyance
| that's slowly crept up to a frustration now. It also happens that
| one screen entirely won't 'receive signal' after sleep until I
| turn unplug/replug the lightning cable
| nickjj wrote:
| A few years ago I had a 10+ year old LCD start to show pink
| horizontal lines and it partially blended and distorted 30% of
| the monitor on the left side.
|
| The interesting part was you could see a decent amount of the
| original screen's contents even if you had a different screen
| being shown such as being behind a lock screen. So imagine a
| scenario where you had your monitor on with something sensitive
| open, you turn on your lock screen and go AFK. You could come
| back 15 minutes later and still see a third of whatever apps you
| had open at like 50% opacity and it blended through with the pink
| lines and login screen. It was like an acute burn-in effect.
|
| I don't have a picture of it but it was very similar to this
| effect (I found this when Googling):
| https://linustechtips.com/uploads/monthly_2017_04/IMG_201704...
| alin23 wrote:
| Sounds very similar to my own issue, described here:
| https://news.ycombinator.com/item?id=32630077
| nickjj wrote:
| Oh nice. Yeah it sounds very similar. I never did a touch
| test to see if it was hotter but heat makes sense. The pink
| lines and distortions were always present once the problem
| started but eventually the previous image would fade away. I
| remember trying everything with no change (different
| computer, drivers, cables, adapter types, etc.) and also
| chalked it up to a hardware problem.
| sinoue wrote:
| I was really hoping you were an entomologist and that you had a
| bug collection of insects attracted to monitors & TVs!
| traceroute66 wrote:
| One thing I learnt recently is that Windows 10 or below is
| incapable of remembering window positions. You need to buy third-
| party software. Microsoft _finally_ fixed this with Windows 11.
|
| I'm not making this up, its well documented on many internet
| forums, including Microsoft's own.
|
| Incidentally, made me happy to be a Mac user. Since Apple never
| had that problem. Infact OS X is magical in how it deals
| seamlessly with unplugging/plugging external monitors (and no, I
| don't use an Apple external monitor).
| quercusa wrote:
| It's not so simple. I've had two (different type) Dell 27"
| monitors on Win10 for years and never had a problem with losing
| window positions, until I accepted an 'upgraded' Nvidia driver
| (27.x to 30.x) a few weeks ago. I rolled back the driver
| version and it's all good again.
| [deleted]
| tristor wrote:
| I wonder if there's any resources that validate monitor DDC
| capabilities. It sounds like a lot of the issues are caused by
| bad monitor firmware
| cesarb wrote:
| About device serial numbers, see also:
| https://devblogs.microsoft.com/oldnewthing/20041110-00/?p=37...
| "Why does Windows not recognize my USB device as the same device
| if I plug it into a different port?" (2004)
| alin23 wrote:
| Yes, looks like the same thing but applied to USB peripherals
| instead of DDC-capable ones.
|
| I guess changing the serial number and recompiling the firmware
| for every device is too hard or too slow for some reason.
| bluedino wrote:
| Makes me think of the "common knowledge" that Macs don't work
| properly with external monitors. Fuzzy fonts etc
| kmeisthax wrote:
| That's moreso because Apple has a Strongly Held Belief that UIs
| should never render at fractional scale factors. If it needs to
| be 150%, it will render a larger virtual desktop at 200% and
| then downscale.
|
| Contrary to Apple, monitor manufacturers have a Strongly Held
| Belief that monitors should all be one marketable resolution
| (e.g. 4K) and shape (16:9 widescreen or wider) and users just
| pick a size. Bigger monitors shouldn't have more pixels in
| them.
|
| The Apple philosophy says that 4K 27" monitors are
| fundamentally broken hardware that the OS needs to fix at the
| cost of some display clarity. The manufacturer philosophy says
| that DisplayPort can't run 5K off a single cable[0] and that
| nobody wants letterboxing when watching a movie on their new
| laptop. Apple designs the monitor around what the OS and user
| need while display manufacturers design around whatever they
| can buy and repackage.
|
| Of course macOS has fuzzy fonts even at 1x, but that's not a
| display problem. That's a _different_ Strongly Held Belief.
| Microsoft deliberately bends fonts to fit the pixel grid (they
| call this ClearType) while Apple uses antialiasing to remain
| faithful to the glyph shapes as they were originally designed.
|
| [0] Or at least this was true as of the release of the iMac 5K
| almost a decade ago. This is not true anymore but no
| manufacturer is touching 5K anyway.
| trasz wrote:
| I'd attribute this to the fact that the way technology is
| organised follows how the groups of people who develop it are
| organised. The Ghost Of The New Machine thing; "if you put
| database folks and kernel folks into the same office, you'll
| end up with parts of database in the kernel".
| zajio1am wrote:
| Problem is that fractional scale factors are broken, unless
| your GUI is completely vector-based. While OS can render
| texts and vector graphics on fractional scales, bitmaps has
| to be scaled, which makes them blurry.
| kmeisthax wrote:
| Bitmap scaling doesn't become blurry if you have enough
| resolution (e.g. going from 2x to 1.5x is fine). Vector
| scaling breaks because layout calculations don't take the
| pixel grid into account.
|
| The most egregious example of this is CSS floats, where
| browsers have to do all sorts of hacks to ensure that
| percentages still add up to 100% _after rounding_.
| Otherwise fractional zoom factors cause layouts to have
| pixel gaps or overflow onto other pages. Fonts get around
| this with hinting but there 's no way to hint a CSS layout.
| politelemon wrote:
| This is typical but poor gymnastics which grants benefit of
| the doubt to brand loyalty. Manufacturers hold no such
| belief, they are beholden to standards to cater to a wide
| variety of configurations and setups. Implying it's not made
| for users is poor form, and simply false.
| jahewson wrote:
| If this were true then companies other than Apple would
| offer monitors that actually do cater to non-broken
| configurations but they don't. The parent post does a great
| job explaining the technical trade-offs and economy of
| scale optimisations that manufacturers have decided to
| make, whereas you have only an ad-hominem attack to offer.
| aeharding wrote:
| I found Lunar very helpful in a South facing apartment with floor
| to ceiling windows. Without Lunar I had to spend a minute
| adjusting each monitor, multiple times a day. It solved a problem
| I never experienced in a home with normal windows.
| alin23 wrote:
| That's also how Lunar started actually :)
|
| I got my first Mac + monitor setup in an apartment with the
| desk on a closed balcony. It was driving me crazy to press the
| fiddly LG joystick to get to the brightness menu all day long,
| so I can follow the ever changing ambient brightness.
|
| It's also why Lunar v1.0 only had sunrise/sunset based
| automatic brightness, not even hotkeys for adjusting the
| brightness manually.
| ajb wrote:
| Fun fact: in some monitors, the EDID flash is writable via the
| HDMI cable (because the manufacturer forgot to wire the write
| disable pin to disable this). I know this, because my employer at
| the time shipped one like that (facepalm).
|
| That means that your laptop can corrupt the EDID.
|
| Windows and MacOS actually ship with a database of 'corrected
| EDIDs', in which they look up the EDID of your monitor and use
| instead the one in the DB, because they know the original is
| broken. TBF, I think this information is provided by the
| manufacturer.
|
| If you don't need DDC for anything else, the monitor-swapping
| issue could be fixed by wiring a 4kb I2C flash chip to the DDC
| pins of the hdmi cable (in place of the monitor, and writing it
| with a copy of the EDID, with the serial number incremented. A
| lot of work though. Maybe there is a place for someone to make an
| HDMI cable with a small embedded microcontroller, for fixing this
| and other DDC issues.
| bombcar wrote:
| So many monitors run on similar controllers internally - it would
| be absolutely wonderful if one or more of those had open source
| firmware so these bugs could be fixed
| rootusrootus wrote:
| Would also be wonderful if they could use a halfway modern CPU
| so the monitor didn't take 30 seconds to wake up. My CRG9 takes
| long enough that my macbook will fall asleep again from the
| password prompt as I'm waiting for the monitor to light up, if
| I don't keep hitting keys.
| swayvil wrote:
| davzie wrote:
| The AI comments are getting out of hand
| samarthr1 wrote:
| How can you tell that it was an AI post though?
| trasz wrote:
| Sony's CRTs didn't use shadow masks; they used a wire-based
| thingy instead.
|
| Also humans don't have a way to generate magnetic field to
| distort it.
| swayvil wrote:
| No human would use allcaps italics like that.
| robocat wrote:
| Could you give us a slice-of-life description of your AI
| life? Preferably without the violent or sexual aspects?
| bredren wrote:
| Also: "sent it to a tech"
| oyashirochama wrote:
| When the AI is cringe.
| [deleted]
| swayvil wrote:
| What's the preferred term?
|
| Boffin?
| Vecr wrote:
| Are you sure it's not some old USENET/e-mail/early web
| troll/joke thing? It has that sort of quality. Bending your
| TV's aperture grill by focusing too hard on a small part of
| your screen, using some sort of supposed psycokinetic
| effect sounds more like the product of the 1990s Internet
| than the product of a 2020s AI/text prompt system.
| lifeisstillgood wrote:
| >>> That will sometimes, not always, but deterministically when
| it's most annoying,
|
| Oh yes. totally true :-)
| BIKESHOPagency wrote:
| This is a kind of look behind the curtain that we rarely get from
| large software developers. Users are often told by someone down
| the chain in support it works or doesn't and no explanation why.
| I find this very fascinating and as a saas developer that makes
| an app that has to work with external hardware that I often don't
| have to test on very encouraging. Sometimes, there's no fix and
| it's not my fault.
| alin23 wrote:
| I'm also moving towards software that is less dependent on
| hardware especially because of the headaches that Lunar brought
| me over the years.
|
| You're probably in a much better spot, SaaS is still the best
| way to make money as a developer, if you don't have to provide
| too much support.
| alluro2 wrote:
| That "if" does a lot in that sentence :) Just had a typical
| fun experience:
|
| Customer: Your platform doesn't work, when we do this, A
| happens
|
| Me: Hm, we don't have that feature, but I understand your
| use-case. We could deliver this new feature by tomorrow, but
| using it that way also inherently means B would happen in
| such and such cases, so just want to make sure that's what
| you want?
|
| Customer: Let us know when the bug has been fixed, it's
| urgent and we're losing money because of you (they had 1
| month free trial)
|
| Me:: It's not a bu...okay, we will
|
| Me: * works all night, builds a new feature, fully polished,
| notifies customer
|
| Customer after 2 days: Yet ANOTHER bug with your unstable
| software!! * describes B
| teaearlgraycold wrote:
| Unless this was a customer you absolutely needed you should
| not have given them control over your immediate development
| schedule. Offer refunds if relevant (sounds like not the
| case). Keep your sanity instead.
| jraph wrote:
| Could recommending a competitor to these people be a good
| business decision?
| alin23 wrote:
| Oh.. that sounds so familiar it almost triggers PTSD-like
| symptoms inside me.
|
| I guess these _vocal_ and _demanding_ people are
| everywhere, no matter how easy and intuitive the software
| is.
|
| I just had someone ask for a new feature and a discount on
| my $6 app a few minutes ago.
|
| We have to come to terms that this is part of the job where
| we have such a close connection to the people that use our
| product.
| [deleted]
| mort96 wrote:
| The first issue, where multiple monitors have the same
| vendor/model/manufacture date/serial number, couldn't that be
| solved by also storing which port it's connected to? That way, if
| you have two HDMI ports, if both monitors have the same UUID, you
| store settings based on port rather than UUID. I don't know if
| this is possible with this new USB-C world, but at least with
| traditional hardware, it seems like the OS knows which port a
| monitor is connected to.
|
| Anyways, interesting post. It's always fun to discover how much
| hardware is just broken and doesn't actually correctly implement
| the protocols or features it's supposed to implement.
| Someone wrote:
| FTA: In standby, the monitor is actually disconnected and
| disappears from the I/O Registry
|
| I think the common case of "multiple HDMI ports" is one where
| users plug in USB-C dongles to magically create them.
|
| In that case, do the HDMI ports disappear from the registry,
| too, so that you can't identify ports across standby?
|
| Even distinguishing a built-in HDMI port from one in a USB-C
| dongle may be difficult if the built-in one secretly is
| connected over USB-C.
| akira2501 wrote:
| The USB is a bus. All controllers and devices connected to it
| have a unique port assignment as well.
| Someone wrote:
| My question is whether that assignment survives standby of
| the PC. Reading
| https://unix.stackexchange.com/questions/336037/mapping-
| of-u..., I'm not sure it does.
|
| Certainly, a bus scan has to happen to detect whether
| devices (including USB hubs) got unplugged or plugged in
| during standby, so if that scanning isn't guaranteed to
| always produce the same result (e.g. because of jitter in
| the timing when various devices come online), I doubt
| that's guaranteed to produce 100% identical information.
|
| It's a _question_ , though. I don't know enough of how this
| work to definitely answer that.
| IshKebab wrote:
| That answer is talking about the kernel assigned device
| names, not the port identifiers which should be stable
| across reboots.
| erichdongubler wrote:
| This should be at least theoretically possible -- in Windows,
| for instance, device file paths are based on connection
| topology, including port address.
| drewtato wrote:
| I'm guessing this is caused by the monitors waking up in
| different orders. The computer tries to set em up as soon as
| possible even if they're in different ports. It would be nice
| if it detects when the collision happens and then put them in
| another list for monitors associated with their port. Or just
| have an option.
| mike_hock wrote:
| If it detects a UUID collision, it should automatically drive
| to the manufacturer, kick in the door and keep punching faces
| until they start assigning proper serial numbers.
| KMnO4 wrote:
| There's no such thing as manufacturers assigning colliding
| UUIDs.
|
| If that happens, then they're just assigning "ID"s.
| mike_hock wrote:
| > If that happens, then they're just assigning "ID"s.
|
| Or "serial numbers," as it were.
|
| The concoction of UUIDs that are neither universal nor
| unique happens in software, but the cause is the serial
| numbers colliding.
| mort96 wrote:
| The manufacturer isn't assigning UUIDs, we're talking about
| what macOS considers a display UUID. MacOS will generate a
| UUID based on the manufacturer, the model, the
| manufacturing date and the serial number, and the intent is
| truly that these UUIDs uniquely identify the display. It
| just doesn't work when multiple monitors have the same
| serial number, which isn't supposed to happen.
| feifan wrote:
| Back when I had two monitors, I got the same cables for both
| and I indiscriminately plugged them into my computer (I had a
| laptop, so plugging/unplugging happened ~daily). So the mapping
| between computer port and monitor definitely wasn't going to
| stay the same.
| Nition wrote:
| You wouldn't use the "which port was it in last" fallback
| option unless you already had multiple saved entries where
| every other bit of data matched.
| mort96 wrote:
| Yeah, it would be a workaround for some cases but not all. It
| would work in the case of a desktop system where the monitors
| are always plugged in, and it would work for the case where
| the monitors go through some kind of USB-C dock (assuming
| it's possible), but not in your case.
| tonyarkles wrote:
| Not as convenient but you could label them, if the port was
| actually factored in.
| klausa wrote:
| I strongly suspect that this is not the full picture.
|
| I had this exact same issue, two displays, always connected to
| the same TB3 Dock, and they would randomly get re-assigned
| after wake-up. Which in my case was doubly irritating, since
| one of those is in portrait mode, so "fixing it" required
| tilting my head to be able to navigate the mouse correctly.
|
| There's a small CLI utility called `displayplacer`[1], that
| basically fixed this for me. I don't... really know what exact
| EDID fields or whatever metadata it's reading, but after I used
| it once to "save" the correct orientation/placement, I could
| reset it to the "correct" one every time after that. Highly
| recommended if that's something you're struggling with.
|
| [1]: https://github.com/jakehilborn/displayplacer
| alin23 wrote:
| Looks like displayplacer uses the standard
| `CGDisplayCreateUUIDFromDisplayID` which the system also uses
| internally: https://github.com/jakehilborn/displayplacer/blob
| /master/dis...
|
| This should be prone to the same issue.
|
| Your problem might actually be caused by a timing bug, where
| the EDID is not fully available in the first few milliseconds
| of the reconnection, and the system doesn't reconcile after
| it becomes available.
|
| displayplacer will get the full picture because it's always
| run a long time after the connection has stabilized.
|
| I can't be certain, but I noticed some slow monitors/hubs do
| have that timing issue by observing the zero/null values for
| UUID in The Monitor Database: https://db.lunar.fyi
| kitsunesoba wrote:
| It's crazy how many aspects of the electronics in monitors
| are seemingly phoned in, even on models exceeding $1000 in
| price. Problems like non-unique IDs and EDID not being
| available right away are such trivial issues to solve and
| probably wouldn't even cost that much in the long run and
| yet here we are.
|
| I wish a company like Framework or system76 would get into
| monitors and open source their monitors' electronics and
| firmware so at the very least, these issues could be fixed
| by the community.
| [deleted]
| tenebrisalietum wrote:
| > There's nothing you can do to fix it
|
| You can buy adapters that forward their own EDID instead of the
| monitors, I think.
| alin23 wrote:
| Yes, man-in-the-middle for EDID was one of the solutions I
| thought about. But that can be a security issue [0] and I
| didn't want to endorse something I don't trust fully.
|
| [0]
| https://git.cuvoodoo.info/kingkevin/board/src/branch/hdmi_fi...
| weaksauce wrote:
| that install script is not correct. $BIN is never set to anything
| so it would thankfully crash at the mkdir -p instead of
| installing to the root directory but either way it wouldn't work
| alin23 wrote:
| Correct, thanks for catching that! I updated the post.
| backspace_ wrote:
| The title should reflect these are mac issues and solutions
| alin23 wrote:
| It's a free form blog post, not a tutorial.
| colechristensen wrote:
| I had a very strange monitor bug a few years ago. Dwarf fortress
| and a weird linux display mode drove my monitor to display a
| freeze frame of what was going on during the bug at about half
| opacity with a bit more of a glitchy feel.
|
| It stayed after reboot, mode changes, OS changes, retriggers of
| the bug etc. etc. etc. to the point where it did not make sense
| at all how the pseudoimage stayed past power cycles and
| everything else I could imagine. I briefly, and quite seriously,
| questioned my sanity trying to figure out what was going on.
|
| Eventually it just went away. Some firmware bug got an image
| stuck in memory or something, but man it was weird.
| solarengineer wrote:
| I wonder if keeping the display powered off and disconnected
| from power supply for a minute or more would have helped in
| your case.
|
| I have run into not-so-funny situations due to capacitors. See
| https://dynamicproxy.livejournal.com/46862.html
| colechristensen wrote:
| I did everything I could imagine including long periods of
| disconnecting power and nothing changed, it was very weird.
| alin23 wrote:
| Author here, it happens right now with my 5 year old LG 27UD88.
|
| When the bottom part of the monitor renders something darker
| (say a Sublime Text window), it also displays a ghost image of
| a lighter previous image (like the browser window with a white
| page).
|
| It started about a year ago, and every time it happens, the
| bottom part of the panel is very hot to the touch.
|
| After letting a fan blow over that part to cool down the LEDs
| behind, the problem went away.
|
| Which leads me to think this is a hardware problem, and the
| panel is giving up on me.
| avian wrote:
| > Blacking out [...] unplug the power cable, and plug it back
| again
|
| As someone with a monitor that's prone to blacking out like this
| (not due to Lunar) and was at one point convinced that the
| monitor got bricked: the key is waiting ~5 minutes before
| plugging the power back in. A quick unplug-plug in a hurry might
| not do it. You need to wait for the internal capacitors to
| discharge to the point where the controller gets properly reset.
| kitsunesoba wrote:
| I've run into this on the older ASUS model PB278Q. It's
| otherwise a decent monitor, if a bit slow to turn on and switch
| sources by modern standards, but once in a while it'll refuse
| to display anything and I'll have to unplug it from power for a
| few seconds to "hard reset" it.
| alin23 wrote:
| Yes, that's a good hint. Most monitor power bricks have very
| large capacitors, especially when they also charge the laptop
| through the Thunderbolt connection.
|
| That's also the point of the LEDs you see on power bricks.
| After unplugging, the LED uses up the capacitor current to
| discharge them faster and also serves as a visual indicator to
| know when it's safe to plug back the cable.
| sroussey wrote:
| Leaving the power off for 5min also has the advantage of
| cooling the machine.
| epakai wrote:
| I have some dells (U2414H) that can get into a really bad
| state. Sometimes unplugging power is not enough. You have to
| remove all potential power inputs including display input
| cables (or shut those devices down too) to get a proper reset.
| tobyhinloopen wrote:
| Funny, i have the exact same display and I've had it randomly
| not work multiple times.
|
| Only unplugging everything seemed to work.
|
| Happened maybe 5 times in the many years ive owned it
| stanmancan wrote:
| Does pressing power while it's unplugged expedite the process
| by attempting to draw power and emptying any capacitors in the
| process?
| Maursault wrote:
| You might speed this up by unplugging the monitor, then holding
| down the monitor's power button for a few seconds to discharge
| its capacitors, then immediately plugging back in and powering-
| on. The only reason I can see to wait 5 minutes is so the
| capacitors will naturally discharge, but holding down the power
| button while the monitor is unplugged should immediately
| discharge them.
| R0b0t1 wrote:
| This is true only for some designs. It's possible you could
| have a power island that doesn't get discharged and also has
| no connection to any buttons when the board is nominally off,
| and that the things in that power island refuse to reset
| properly.
|
| There's a whole area of electronics design related to this
| (unfortunately).
| seri4l wrote:
| Something I learned not long ago on this site: low quality/too
| long HDMI cables can make some monitors go black when the user
| stands or sits on a certain kind of office chair. [1] [2]
|
| Apparently it's a known issue at Dell: [3]
|
| >Surprisingly, we have also seen this issue connected to gas lift
| office chairs. When people stand or sit on gas lift chairs, they
| can generate an EMI spike which is picked up on the video cables,
| causing a loss of sync. If you have users complaining about
| displays randomly flickering it could actually be connected to
| people sitting on gas lift chairs. Again swapping video cables,
| especially for ones with magnetic ferrite ring on the cable, can
| eliminate this problem. There is even a white paper about this
| issue.
|
| [1] https://www.youtube.com/watch?v=voW5kEI7JKE
|
| [2] https://www.youtube.com/watch?v=D6pY4t0k1hk
|
| [3]
| https://support.displaylink.com/knowledgebase/articles/73861...
| AriedK wrote:
| This is an issue at our office. We have some cheaper LG
| monitors that flicker when someone stands up from his gas
| spring chair. The Dell monitors we have don't suffer this
| issue. A paper on the issue:
| https://www.emcesd.com/pdf/uesd99-w.pdf Apparently a dangling
| bag of coins can cause similar issues, but haven't encountered
| that so far.
| stn8188 wrote:
| Thanks for linking Doug Smith's website, he has some
| excellent EMC/EMI info for us hardware engineers.
| exmadscientist wrote:
| > Apparently a dangling bag of coins can cause similar issues
|
| A dangling bag of coins is a famous cheap EMC test for
| products. All of this sounds like monitor vendors cheaped out
| on their EMC and need to have their ESD and Immunity
| certifications reevaluated....
|
| Or maybe it's just the fact that they were dumb enough to
| ship an I2C interface over a cable as part of the industry
| spec. Never ship I2C off-board or this kind of crap happens.
| trinovantes wrote:
| I'm using a Steelcase Leap chair which does use a gas cylinder
|
| This might explain why one of my monitors with a 2m long HDMI
| cable every so often fails to turn on after waking up from
| sleep mode
| annoyingnoob wrote:
| I moved to fiber based cables to solve this. Expensive but work
| great.
| tobyhinloopen wrote:
| This happens to me all the time! I thought I was crazy.
| colordrops wrote:
| I've got a cablematters thunderbolt hub with two DP outputs
| connected to two LG monitors. They aren't exactly the same but it
| doesn't matter, as I'm using Xorg, which doesn't use EDID for
| layouts. It just uses the output names, which are DP-1, and DP-2,
| and sometimes the hub flips them. The only way I've found to
| "fix" this is to use Autorandr, which will update the layout
| based on the EDID, but the output names remain flipped. This is
| still an unsolved problem, because i3 uses the output name rather
| than physical position for where to put workspaces.
|
| My other laptop doesn't have an nVidia GPU and runs Sway/Wayland,
| which doesn't seem to have this issue.
|
| If anyone knows how to solve this I'd be eternally grateful. It's
| been driving me nuts for a year.
| pedrocr wrote:
| If you switch from i3 to sway you can use the serial number
| instead of the port to assign outputs. I think these days it's
| usable with even the proprietary nVidia driver.
| colordrops wrote:
| Oh interesting, I understand that sway with Nvidia is
| developing quickly. I did read maybe less than a month ago
| though that it's still quite glitchy. Will look into it
| again.
| AshamedCaptain wrote:
| A bit of warning if you try to get a firmware update from Dell to
| your monitor. Dell's official stance is "we don't sell monitors
| outside our official channel". If you bought a Dell monitor from
| Amazon, Dell may NOT accept it for a firmware upgrade.
| teetertater wrote:
| Thanks for developing Lunar, I'm a happy user for over a year!
| alin23 wrote:
| Thank you for the kind message! Happy to hear you find it so
| useful :)
| guiambros wrote:
| Another +1 from a happy user! Thank you for developing it. I
| use several times a day, whenever I'm entering/leaving video
| calls, or depending if the site/app has dark mode. It's
| incredibly helpful and reliable!
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