<pulling some offline discussion back into this, I think relevant to others
cheap geeks wanting to use a big tv too>
You're right, the ports on the dock are DP1.2, but the TV is HDMI2.0, so
using an all-in-1 DP-to-HDMI cable, presumably the dongle chip built into
it, but hopefully better being "built in" together than a separate
DP-to-HDMI dongle+cable.
Even using matched dongles and cables had recurring issues, similar to
Linus Tech Tips on youtube using an 8k TV, that required literally 4x HDMI
connections to use the 8k setup, and none would sync with each other.
Using a combo DP-to-HDMI cable resolved this (provided by the TV vendor of
course), but dongle+cable was a no-go.
I've done a fair amount of diag watching the display churn during
power-down, no signal, etc and per xrandr it's typically showing the
correct display modes, and presence of the display (while in power down,
but os seems to know it's not active to use it). KDE, which when it isn't
infuriating me, tends to be what I use, and it just always does a horrible
job of shifting windows, display settings, refresh/resolution, etc during
these transitions of all/some displays at once. It's not only KDE though,
Cinnamon, Mate do it too, seems a systemic issue outside the DE. Plus it
happens with either Intel or Nvidia, so that leaves me staring at the
kernel, or xorg itself being quirky.
I think you're right with a static edid and a device to do it, I've
considered this in the past with some of the magic video adapters that do
this for various odd devices, but were expensive for adapters when I need
2-3 of them (they were over $100ea last I looked). These little single
shot static units might work if I can find one for HDMI-to-HDMI.
However my fear is the problem is more with the DP to HDMI chip that is
translating, either in a dongle or built into a cable, which I think is
where things get flaky (since I have to still "reboot" them occasionally
with a cable pull. If that is glitching, I don't think a static edid
adapter would even help at the hdmi end as I think the issue is more at the
DP and adapter side.
Native HDMi ports would probably work, but no one makes a multi-HDMI card
or dock I've found, at least not for 4k/60 x2 or 3 displays. The docks I
did find were typically DisplayLink chip-based docks, which make crappy
usb-to-video chips with dubious linux driver support, particularly anything
not already 3-4 years old. DisplayLink has always been Linux-unfriendly,
and just not something I'll bother with.
Nothing is ever perfect....
-mb
On Mon, Aug 24, 2020 at 4:48 AM Brian Cluff <
brian@snaptek.com> wrote:
> If all your connections all end up plugging into the HDMI port of the TV.
> You should be able to just plug the EDID device directly into the TV and
> your HDMI cable into it and it should solve all your problems... Unless
> I've missunderstood and you have found some TVs with displayport
> connections on them.
>
> Brian
>
> On 8/23/20 7:00 PM, Michael Butash wrote:
>
> That looks pretty cool, but my dock is 1x TB3 in, and 2x DP1.2 out on
> there, so really the problem is adapting DP1.2 to HDMI there to 2 of the
> displays. My third display mostly sees playstation activities these days
> until I screw around with my failed desktop, but still use 2x TV's with my
> built-in 4k laptop display as 3rd.
>
> I used to use a separate hdmi cable and a DP-to-HDMI adapter, but randomly
> saw someone else having issues with them (particularly with 8k displays
> muxing across them), then got an integrated DP-to-HDMI cable I had better
> hope for (could not find his exact brand). It's a bit better, but still
> occasionally requires reseating. I suspect this is a bug in the
> hardware/firmware on the adapter soc, but who knows.
>
> Maybe what I need is one of those adapters for more hdmi-to-hdmi at the tv
> end, or DP-to-DP for the same at the dock end. I'll look around see if
> something like what you sent me.
>
> Appreciate you look around on this for me, I have really odd issues no one
> ever else much seems to. Perhaps self-inflicted gunshot wounds, but I like
> to think I'm pushing boundaries. ;)
>
> -mb
>
>
> On Sat, Aug 22, 2020 at 10:41 AM Brian Cluff <brian@snaptek.com> wrote:
>
>> I think I've found the solution to your display problems, you just need
>> to buy a 3 pack of these (relatively inexpensive):
>>
>> https://www.amazon.com/FUERAN-stabilizer-Thunderbolt-fit-Headless-4k-3840x2160/dp/B07ZYLGDK3
>>
>> Just read the reviews. It sounds like it solves your exact problem. The
>> reviews also say that it can be used with a displayport to HDMI adapter
>> unlike what the product description says. The product has a lot of
>> chinglish in it so I think what they mean is that it's not a displayport to
>> hdmi adapter.
>> https://www.amazon.com/product-reviews/B07ZYLGDK3/ref=acr_dp_hist_5
>>
>> It appears you need to purchase the correct device for the resolution you
>> want to run and then once plugged in it just tells the system that there is
>> a display connect all the time, even if it's turned off or there isn't one
>> plugged in at all. This is the device that I was mistakenly calling a DPMS
>> proxy in my previous message. I had forgotten that it's actually an EDID
>> proxy, and they are a lot cheaper than when I was trying to solve my
>> similar problems in the past.
>>
>> I hope this helps...
>>
>> Brian Cluff
>>
>>
>>
>> On 8/22/20 8:30 AM, Michael Butash wrote:
>>
>> All valid points and correct Brian, cost vs. function. ~3yr ago when I
>> bought these displays, I was moving from 6x 24" ancient dell lcd's, and got
>> a "good" deal on these for about $650ea, curved samsung 48" 4k/60
>> displays. Couldn't get close to that with a real large monitor, let alone
>> curved (great for my desk) and in fact really couldn't find any period
>> except some off-brand chinese ones I expect to last no more than a year.
>>
>> I'd purchased a CEC injector to play with, but kind of a pain to run and
>> sync 3 of them at once, plus ~$50ea. Was going to try a rs232 adapter on a
>> quad serial adapter, but eventually realized I can live with shutting off
>> the displays manually via good old remote.
>>
>> The problem comes in doing so, you can't really catch and power-down all
>> at once, which causes video subsystem to start resizing from 3 displays, to
>> 2, to 1, then none, which pretty much freaks out KDE and other DE's. KDE
>> has been notoriously horrible about multi-monitor support over the years,
>> window placement/size preservation, random resolution setting resets,
>> things like that. Now add in some dongles that randomly require a physical
>> disconnect to resume proper function randomly, every day, sometimes
>> multiple times a day if I have power management shutting down displays, and
>> it gets infuriating rather quickly. This was on my desktop with a
>> dedicated video card even!
>>
>> Now I'm using my laptop and the TB3 dock, which I find if I simply walk
>> up and yank the dock TB3 connector, so all external displays drop at once,
>> then power them down, they actually work fairly normally. I have to
>> disable power down of displays, but since the tv's won't shut off entirely
>> anyways, isn't that big a deal, other than the constant heat these generate
>> and my failing old AC in the house.
>>
>> I'm a bit more surprised HDMI still this day doesn't support DPMS-type
>> functions to some extent, even if "legacy" vs. only CEC. Likewise I'm
>> surprised companies like samsung don't just include a DP port on their TV's
>> too, as it's more common to see folks like yourself and I using TV's as
>> displays, as most tv's are better quality and price than any available
>> "computer monitor" unless you need/want 144mhz gaming refreshes (that your
>> eyeballs can't see anyways).
>>
>> I figure at some point a developer might buy a few of these tv's and
>> realize how asinine this all is to use to resolve it, but considering here
>> we are in 2020 and my first reports of some of this stuff began a decade or
>> more ago, perhaps not. KDE is still working on trying to fix window
>> placement a decade or two on, seeing this just today...
>> <https://www.phoronix.com/scan.php?page=news_item&px=KDE-Apps-Window-Pos>
>>
>> -mb
>>
>>
>> On Fri, Aug 21, 2020 at 10:16 PM Brian Cluff via PLUG-discuss <
>> plug-discuss@lists.phxlinux.org> wrote:
>>
>>> The problem with your setup is that you're using TVs for multiple
>>> displays. Like you said, TV's don't understand DPMS so it's impossible to
>>> get them to power down on command. Most newer TVs do understand CEC and
>>> it's possible to get a CEC injector (I believe NVIDIA doesn't handle it in
>>> their cards) to send a signal for the TV to power itself off/on when you
>>> want it to. The biggest problem is that when TVs turn off, they stop,for
>>> the most part, reporting on the cable that they are there, so from the
>>> point of view of your system, you are unplugging and plugging in the TV's
>>> from the system, probably in some random order, and the system has to
>>> quickly deal with handing changing scenarios of one monitor configuration
>>> after another as the TVs turn on... It's probably freaks out because it's
>>> asked to setup a display on one TV.... no wait 2 TVs... Just kidding 3
>>> TVs... but it's still trying to handle the first one by the time it's asked
>>> to handle the 3rd one. I have a feeling that TV's also don't have the
>>> unique ID's that monitors have so it will also struggle to automatically
>>> place them back in the correct order once they are all up and running if
>>> you are using the same model TVs for all your displays.
>>>
>>> I personally use a single 50" 4K display for my desktop and other than
>>> having to turn it on and off by hand, it has worked flawlessly for the past
>>> 5 or 6 years... but then again, I'm only using the one TV for my display.
>>> Before that I used a 3 monitor setup, with actual computer monitors and I
>>> didn't have any problems at all with that. My brother had a system with I
>>> believe 16 computer monitors and that worked very well as well, but again
>>> that were actual monitors.
>>>
>>> I think I remember coming across a device that was a DPMS proxy that
>>> might fix your problem. It basically sits between you computer and display
>>> and fakes a monitor signal to your computer so that your TVs don't appear
>>> to be disappearing and reappear to your computer constantly.
>>>
>>> You could also hard code your display setup in your Xorg.conf so that it
>>> would have no choice but to setup your display like you like it, but that
>>> could make things difficult/stange for you at a later date if you ever
>>> change your display setup.
>>>
>>> Or, you could always get real computer monitors, but that would be very
>>> expensive which is probably why your using TVs in the first place.
>>>
>>> Brian
>>>
>>> On 8/20/20 5:25 PM, Michael Butash via PLUG-discuss wrote:
>>>
>>> I have had lots of issues with video and adapters the past few years,
>>> mostly as I'm forced to use them. My nvidia 1070 in my desktop has 3x
>>> DP1.2 ports and 1 HDMI2.0. I have 3 displays, so I use the 3x DP1.2 ports,
>>> and run those through adapters to HDMI2.0 on my Samsung TV's I use for
>>> monitors. Non-stop chaos ensues during power-down and up every day,
>>> something different, every linux desktop hates it. Often one display or
>>> another will freak out, and I end up; having to hard disconnect the adapter
>>> (ie, reboot it) to work again or it'll come up stuck in 768x1024 (on a 48"
>>> tv...).
>>>
>>> I found HDMI doesn't handle DPMS sort of power-off modes as vga, dvi,
>>> dp, or most methods of displays to handle soft power-off scenarios, ala
>>> just power down displays. When my laptop powers them down, they remain on
>>> with no signal, which seems to just confuse the video card and adapter that
>>> both freak out. This seems to have a profound effect on displaya and video
>>> cards that don't realize most displays are now hdmi...
>>>
>>> Graphic subsystems are a basketcase these days under linux, mostly
>>> because of these damn adapters, dongles
>>> <https://www.youtube.com/watch?v=-XSC_UG5_kU>, and vendor wars. Intel,
>>> that wants to sell all the things, including the most useless gpu on the
>>> earth, injects themselves into everything, and always cause me issues as I
>>> can't convince the os to use the (real) nvidia gpu. Probably the same sort
>>> of issue if an intel gpu is around with AMD. Last I used an AMD GPU some
>>> 4-5 years ago, it was an issue. Nvidia Prime via Intel is still sketchy af.
>>>
>>> Even on a dedicated nvidia gpu in a server-ish xeon system, with
>>> DP-to-whatever adapters I had nothing but issues. My latest iteration is
>>> my laptop (xps 9560) and a thunderbolt3/usb-c dock with 2x 4k/60hz outputs
>>> via one-piece DP-to-HDMI cables. I still have quirks, but I've learned to
>>> work around, and now somewhat understand really odd hardware behaviour
>>> enough to reproduce it. Occasionally I still need to disconnect a display
>>> at the DP-to-HDMI cable I use now, which is again oddly random.
>>>
>>> I don't like the adapters, but my 48" TV's I use for displays don't
>>> often come with DP ports native, and using HDMI comes with power management
>>> oddities. A lot depends on your cabling and even display these days.
>>>
>>> -mb
>>>
>>>
>>> On Wed, Aug 19, 2020 at 1:05 PM Seabass via PLUG-discuss <
>>> plug-discuss@lists.phxlinux.org> wrote:
>>>
>>>> No, on the desired monitor, it still black screens.
>>>>
>>>> Works just fine (Even without that parameter) on something that has a
>>>> direct HDMI cable, though. (TV)
>>>>
>>>> > Message: 6
>>>> >Date: Tue, 18 Aug 2020 16:23:47 -0700
>>>> > From: Aaron Jones <retro64xyz@gmail.com>
>>>> > To: plugaz@codezilla.xyz, Main PLUG discussion list
>>>> > <plug-discuss@lists.phxlinux.org>
>>>> >Subject: Re: KMS but AMDGPU And Black Screen
>>>> > Message-ID: <6B7D5942-0F2F-4DAE-A54A-19215718DCF2@gmail.com>
>>>> > Content-Type: text/plain; charset="utf-8"
>>>> >
>>>> > https://bugzilla.redhat.com/show_bug.cgi?id=1594488
>>>> >
>>>> > Set amdgpu.dc=0 in bios and it will work but without hdmi sound.
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>>>
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>>
>>
>>
>
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