[GTALUG] USB-C port was Aging Dell monitor (U3011)

[Michael Hill via talk]

On Sat, Mar 10, 2018 at 12:02 PM D. Hugh Redelmeier via talk

According to
<http://www.dell.com/ed/business/p/dell-u3011/pd>
the monitor has
DisplayPort, audio connectors (supports 5.1 channel audio
connection), two HDMI 1.3 and two DVI-D connectors with
High-Bandwidth Digital Copy Protection (HDCP).
So the right way of connecting to a T450 should be DisplayPort to
DisplayPort.

I've switched out the ThinkPad for a T480, which has *no* DisplayPort
connector but brings back HDMI (lower resolution with the Dell
monitor) and forces me to spend seventy bucks on a new cable (USB-C to
DisplayPort).

After the screen blanks, the monitor refuses to wake up. Sometimes,
corrupt images (very gradually) appear in bands. When the monitor is
asleep, Fedora thinks it's still there and leaves open windows on it,
completely inaccessible. Powering it off and on does nothing, and it
needs to be unplugged/reconnected.

Am I missing a BIOS setting? (There were many that needed to be set
initially.) Is this a driver problem or should I file a bug? Happens
on Xorg and Wayland.

Mike
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[Michael Hill via talk]

Coincidental and potentially related blog post:

https://christian.kellner.me/2018/10/24/thunderbolt-port-guide-t480s-force-power/
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[Michael Hill via talk]

Solution (for now): set BIOS Thunderbolt Security setting to DisplayPort.

Carry on.
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[Giles Orr via talk]

One possible solution (which you may not need anymore, but I thought I'd
throw it out there) is to run xrandr or arandr to switch off the monitor.
This would bring all the windows back onto the primary monitor. You could
then try using [xa]randr to turn the monitor back on, which might "refresh"
the monitor.

All guesses. Hope this helps.

Post by Michael Hill via talk
Solution (for now): set BIOS Thunderbolt Security setting to DisplayPort.
Carry on.
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[Michael Hill via talk]

One possible solution (which you may not need anymore, but I thought I'd throw it out there) is to run
xrandr or arandr to switch off the monitor. This would bring all the windows back onto the primary
monitor. You could then try using [xa]randr to turn the monitor back on, which might "refresh" the
monitor.

Thanks, Giles. I think I've come to an understanding with the BIOS settings.

(ThinkPad) Thunderbolt Security Level can be:

No Security
User Authorization
Secure Connect
Display Port [sic] and USB

If I choose the first two in the BIOS, I can modify the settings in
the dedicated Thunderbolt settings panel in Fedora. I can even choose
to disable Thunderbolt support in the panel by setting it to
DisplayPort and USB. I can't remember how Secure Connect behaved (or
why it was unsuitable), but I'll try it again when I get a chance.

If I choose the last setting in the BIOS, the Settings panel says
"Thunderbolt support has been disabled in the BIOS." As much as I'd
like to have options, this seems to be the only setting that permits
the external monitor to be recognized when I jiggle the mouse. Even
the same setting in Fedora, although it starts with good intentions,
forgets after a while and I need to resort to unplugging/replugging.

Mike