Unknown Display

[Bob]

** Reply to message from ??????? ???? ?????? ?? <toshazed at gmail.com> on Thu, 12
May 2022 17:43:40 +0600

> Dear Bob
> Peace be upon you.
> 
> ???, ? ??, ???? ?????? ??:?? AM ??? ?????? Bob <
> ubuntu-qygzanxc at listemail.net> ???????:
> 
> > I have searched the internet and the Ubuntu bugs for this problem without
> > success.
> >
> > I updated a system from 21.10 to 22.04 and noticed that when the screen is
> > blanked by no keyboard or mouse activity that the backlight in the monitor
> > is
> > still on.  The settings -> Displays has "Unknown Display" which I assume
> > means
> > the system does not know what commands to send to the monitor to shut it
> > off.
> > I booted a live DVD of 21.10 and the settings has the display as 'AOC 22" '
> > which is correct and the screen blanking works correctly.  So it seems
> > that the
> > definition for the AOC displays have been removed from 22.04.  I think I
> > can
> > fix this by coping the AOC definitions from 21.10 to 22.04.
> >
> > What is the file name of the file that contain the display definitions?
> >
> 
> Please read out this --
> https://engineerworkshop.com/blog/adding-a-portable-usb-monitor-to-ubuntu-how-to-set-up-a-displaylink-driver/
> May be it will help you as you may be using AOCI1659FWUX model portable
> monitor.
> 
> For software download --
> https://www.synaptics.com/products/displaylink-graphics/downloads/ubuntu
> 
> with regards

Thanks to all that responded.

Sorry for the delay in responding.  I have just moved 1600 miles and everything
has not been unpacked.

I found the extra displays to check if a different display would change the
problem.  All the displays are VGA.  The display I had connected to the system
was an AOC, the other displays were another AOC and an eMachine display (none
had a USB connector).  All three behave the same way on Ubuntu 22.04, the
display screen is blanked and the backlight is on.  This behavior is different
on Ubuntu 21.10, the display is blank and the backlight is off.  A minor nit is
on 21.10 the settings->display shows the display manufacture name, on 22.04 the
display manufacture name is "Unknown Display".

I have discovered that the settings have the following options

"settings->Power->Screen Blank" with a time value to be selected and the
following text on the next line "Turns the screen off after a period of
inactivity"

"settings->Privacy->Screen->Blank Screen Display" with a time value to be
selected and the following text on the next line "Period of inactivity after
which the screen will go blank"

The two options have different actions but seem to be connected because
changing the time on one changes the time on the other.

My guess is that the update changed the action for Ubuntu 22.04.  I would like
the 21.10 behavior, that is to turn off the display not just blank the display.

-- 
Robert Blair


By academic freedom I understand the right to search for truth and to publish and teach what one holds to be true.  This right implies also a duty; one must not conceal any part of what one has recognized to be true.  -- Albert Einstein