KMS but AMDGPU And Black Screen

[Michael Butash]

Totally get you, just can't stack these things, ala DP-to-HDMI converter,
then another "active" device ala even these edid devices.  Sadly what I
need is an active edid magic box that takes DP1.2 in, spits out HDMI2.0,
supports full 4:4:4 4k/60, and allows me to futz with the edid hard.  I
spent some time looking around amazon, nada there, but need to expand
searching some.  These were far more common prior, but not so much now, and
def not at 4k res.

I've not had an issue using 6 or 10 foot cables, or a combination of both,
with or without dongle - they either work, or don't.  The cable solution
I'm using now is an all-in-1 cable
<https://www.amazon.com/gp/product/B07MXV9SNT/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1>,
DP on one end, built in converter, and HDMI out on the other end, and 10ft
for all (figured I'd try consistency).  I still seem to always get one tv,
the same one, that sometimes refuses to start, like this morning.

I typically first thing remote both the tv's on, dock disconnected from
laptop TB3 port.  TV's boot up, no signal.  I plug in my TB dock, typically
a few seconds later the desktop adjusts and brings up both TV's.  Just
randomly, and it's not been in a good week or more, the first tv on the
first dock port will not start, but the os thinks it's there.  I've
verified this before with xrandr.  I then grumble, go to the dock and
physically disconnect the DP port, plug it back in, and suddenly it'll work
again, sometimes days, sometimes weeks, until it screws up again.

My desktop would do this with a dongle converter + hdmi cable, some 6ft,
one 10. and the displays not starting would randomly change, requiring the
same hard unplug/plug at the DP port.  I was hoping the combo cable would
help this trying with my laptop, but mostly the same.

It's like whatever chinese adapter chip they use are clones of a clone of a
clone at this point, and just somewhat flaky crap.  Like what you get with
flaky serial adapters, sd-radios, and other cheap electronics from wish or
alibaba, but the bad clones are so pervasive now, you can't NOT get a piece
of crap part anywhere.

-mb


On Tue, Aug 25, 2020 at 4:25 PM Brian Cluff via PLUG-discuss <
plug-discuss at lists.phxlinux.org> wrote:

> On 8/24/20 10:55 AM, Michael Butash via PLUG-discuss wrote:
> > I did look closer at the cheap EDID adapters Brian sent, and looking
> > at like models a few specifically state "not compatible with DP to
> > HDMI adapters", which is exactly my scenario.  I learned trying to use
> > dp-to-hdmi adapters with "active" thin hdmi cables did not work, and
> > no other active translation seems supported with more than one,
> > including these sadly.
>
> Yes they description says that, but like I said in my message, I believe
> they were trying to say that their device isn't DP to HDMI adapter... If
> you read the reviews there are several people on there describing your
> exact problems with the DP to HDMI conversion and says that it was the
> perfect thing to fix their problems and that they do indeed work with DP
> to HDMI conversion.  If can't find one that has the correct male female
> sides, you could always get a handful of gender changers and make it
> work like that.
>
> Also, are you cables from your machine to display very long.  I found
> that I had a devil of a time getting anything over 6 feet to work
> reliably at all no matter what the quality of cable.  Once I figured
> that out and moved my machine closer I found that even my cheap cables
> would drive my display.... It makes sense considering the signal is
> throwing something in the neighborhood of 18Gbps at the display....  The
> shorter the cable the better.
>
> Brian Cluff
>
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