[lug] Dell Optiplex 9020 + ubuntu + 4k monitor

[Bear Giles]

I haven't worked through all of the permutations of cabling yet but

 - DP -> HDMI dongle -> KVM gives me low resolution
 - DP -> DP cable gives me high resolution
 - mini-DP (on second Linux system) -> HDMI dongle -> KVM gives me high
resolution.

I have a DP -> HDMI cable - no dongle required, but I haven't tried it with
either the KVM or direct connection yet.

I also haven't checked whether the system now realizes that it can use 4k
with the dongle and KVM. I wouldn't be surprised if a driver doesn't
recognize a monitor supports 4k via one mechanism but can use that
information if it's obtained via a different mechanism.

Maybe I'm cynical but I had a lightweight dell laptop - the niche now
filled by chromebooks - that could no longer support its video for a few
releases. I happened to discover that I could still bring up an external
display with the VGA port... and that once I had established a connection
with the external VGA port I could use the laptop's display without any
problems. ?!?!

It's not a problem at home but the entire point of these lightweight
laptops is that it's not a big loss if you lose one while traveling.
Needing to be able to connect to an external VGA monitor sharply limits the
functionality of them. Some hotels had a panel with different types of
connectors but many didn't.

In later updates the monitor started working again.

On Fri, Nov 8, 2019 at 9:26 AM D. Stimits <stimits at comcast.net> wrote:

>
> On November 7, 2019 at 6:12 PM "D. Stimits" <stimits at comcast.net> wrote:
>
>
> On November 7, 2019 at 10:14 AM Bear Giles <bgiles at coyotesong.com> wrote:
>
> (oops - there is a DisplayPort to HDMI dongle on the tail end of the KVM
> cable. But I use the same model in several other places AND have used this
> specific dongle as well.)
>
> ...
> The KVM may not pass through the EDID. Have you tried direct cable?
>
> ...
> Sorry, replying to my own reply. I thought of something else to add: KVMs
> may actually intercept the EDID and send their own based on the
> capabilities of the KVM, or else filtering out resolutions and other
> settings which are beyond the KVM.
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