I have just recovered control of my HTPC ;
It has two HDMI sockets at the rear.
One is connected by a long lead to a widescreen TV.
The second is connected to a 10 inch monitor sittig on top.

However!

Cinnamon is treating them as two adjacent screens.
I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.

I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.

The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
This is rapidly becoming a hobby again!

Alan

--
Linux Mint 21.1 kernel version 5.15.0-91-generic Cinnamon 5.6.8
AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda

On 1/11/2024 8:36 AM, pinnerite wrote:
> I have just recovered control of my HTPC ;
> It has two HDMI sockets at the rear.
> One is connected by a long lead to a widescreen TV.
> The second is connected to a 10 inch monitor sittig on top.
>
> However!
>
> Cinnamon is treating them as two adjacent screens.
> I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.
>
> I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.
>
> The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
> This is rapidly becoming a hobby again!
>
> Alan
>
>

The keyword might be "Mirror".

An alternate alignment is "Span".

When you operate a laptop and use the hotkey,
these might be modes just about any OS provides.
The hotkey toggles through all the modes,
panel, external, panel+external mirror, panel+external span .

It is desktops, where you don't have the hotkey
(and presumably some little ACPI gizmo is missing).

In any case, look for "Mirror" and see what you can find.

Paul

On 2024-01-11, Paul <nospam@needed.invalid> wrote:
> On 1/11/2024 8:36 AM, pinnerite wrote:
>> I have just recovered control of my HTPC ;
>> It has two HDMI sockets at the rear.
>> One is connected by a long lead to a widescreen TV.
>> The second is connected to a 10 inch monitor sittig on top.
>>
>> However!
>>
>> Cinnamon is treating them as two adjacent screens.
>> I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.
>>
>> I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.
>>
>> The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
>> This is rapidly becoming a hobby again!
>>
>> Alan
>>
>>
>
> The keyword might be "Mirror".
>
> An alternate alignment is "Span".
>
> When you operate a laptop and use the hotkey,
> these might be modes just about any OS provides.
> The hotkey toggles through all the modes,
> panel, external, panel+external mirror, panel+external span .
>
> It is desktops, where you don't have the hotkey
> (and presumably some little ACPI gizmo is missing).
>
> In any case, look for "Mirror" and see what you can find.
>
> Paul

Look under Display from the start menu, which is under system settings.

In/under Desktop, from main menu there us an option to Show icons on all
desktops.

On 1/11/2024 3:47 PM, Gordon wrote:
> On 2024-01-11, Paul <nospam@needed.invalid> wrote:
>> On 1/11/2024 8:36 AM, pinnerite wrote:
>>> I have just recovered control of my HTPC ;
>>> It has two HDMI sockets at the rear.
>>> One is connected by a long lead to a widescreen TV.
>>> The second is connected to a 10 inch monitor sittig on top.
>>>
>>> However!
>>>
>>> Cinnamon is treating them as two adjacent screens.
>>> I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.
>>>
>>> I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.
>>>
>>> The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
>>> This is rapidly becoming a hobby again!
>>>
>>> Alan
>>>
>>>
>>
>> The keyword might be "Mirror".
>>
>> An alternate alignment is "Span".
>>
>> When you operate a laptop and use the hotkey,
>> these might be modes just about any OS provides.
>> The hotkey toggles through all the modes,
>> panel, external, panel+external mirror, panel+external span .
>>
>> It is desktops, where you don't have the hotkey
>> (and presumably some little ACPI gizmo is missing).
>>
>> In any case, look for "Mirror" and see what you can find.
>>
>> Paul
>
> Look under Display from the start menu, which is under system settings.
>
> In/under Desktop, from main menu there us an option to Show icons on all
> desktops.
>

I have a suspicion that refers to desktop icons in the upper part of the display.

Window icons in the panel (Taskbar), don't seem to be interested in
spreading across two monitors, any time soon. The "traditional desktop"
is missing from the Welcome Screen, and playing with Add Panel or Applet
settings is a waste of time. The notion of "Linking" that the Display control panel
refers to, is not any notion of Linking I'm aware of. The monitors exist
in a 2D plane, and you can orient the monitors with respect to one another.
I don't know what the word "link" exactly has to do with it. Link seems
to mean "Hey, we aren't Mirroring right now".

The hardware, there is two generations of hardware spanning support.
But it requires, as a general rule, identical monitors. You can connect
three 1920x1080 monitors and the hardware would treat that as a "5760x1080 surface".
That's the hardware spanning support. And if there was some way to do that,
then the Display control panel would be fooled into thinking it was
working with just one monitor (5760x1080). And all the decorations
would behave themselves.

Attempting to "Add Panel" on my setup, to the second monitor,
just caused the panel on the first monitor to move to the
second monitor. This is not the notion of "Add" I would expect.
It's "Move" that it is doing.

Paul

On Fri, 12 Jan 2024 05:34:42 -0500
Paul <nospam@needed.invalid> wrote:

> On 1/11/2024 3:47 PM, Gordon wrote:
> > On 2024-01-11, Paul <nospam@needed.invalid> wrote:
> >> On 1/11/2024 8:36 AM, pinnerite wrote:
> >>> I have just recovered control of my HTPC ;
> >>> It has two HDMI sockets at the rear.
> >>> One is connected by a long lead to a widescreen TV.
> >>> The second is connected to a 10 inch monitor sittig on top.
> >>>
> >>> However!
> >>>
> >>> Cinnamon is treating them as two adjacent screens.
> >>> I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.
> >>>
> >>> I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.
> >>>
> >>> The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
> >>> This is rapidly becoming a hobby again!
> >>>
> >>> Alan
> >>>
> >>>
> >>
> >> The keyword might be "Mirror".
> >>
> >> An alternate alignment is "Span".
> >>
> >> When you operate a laptop and use the hotkey,
> >> these might be modes just about any OS provides.
> >> The hotkey toggles through all the modes,
> >> panel, external, panel+external mirror, panel+external span .
> >>
> >> It is desktops, where you don't have the hotkey
> >> (and presumably some little ACPI gizmo is missing).
> >>
> >> In any case, look for "Mirror" and see what you can find.
> >>
> >> Paul
> >
> > Look under Display from the start menu, which is under system settings.
> >
> > In/under Desktop, from main menu there us an option to Show icons on all
> > desktops.
> >
>
> I have a suspicion that refers to desktop icons in the upper part of the display.
>
> Window icons in the panel (Taskbar), don't seem to be interested in
> spreading across two monitors, any time soon. The "traditional desktop"
> is missing from the Welcome Screen, and playing with Add Panel or Applet
> settings is a waste of time. The notion of "Linking" that the Display control panel
> refers to, is not any notion of Linking I'm aware of. The monitors exist
> in a 2D plane, and you can orient the monitors with respect to one another.
> I don't know what the word "link" exactly has to do with it. Link seems
> to mean "Hey, we aren't Mirroring right now".
>
> The hardware, there is two generations of hardware spanning support.
> But it requires, as a general rule, identical monitors. You can connect
> three 1920x1080 monitors and the hardware would treat that as a "5760x1080 surface".
> That's the hardware spanning support. And if there was some way to do that,
> then the Display control panel would be fooled into thinking it was
> working with just one monitor (5760x1080). And all the decorations
> would behave themselves.
>
> Attempting to "Add Panel" on my setup, to the second monitor,
> just caused the panel on the first monitor to move to the
> second monitor. This is not the notion of "Add" I would expect.
> It's "Move" that it is doing.
>
> Paul

Update:

1. Good news. When the TV is set for HDMI input and I run anything from Mythtv, any accompanying audo does come through the sound-bar. It always worried me that it might not.

2) Bad News. Selecting "Mirror" from Display caused the system to completely cut off the second screen and it took quite a while to get it back.
It looks like I have to disconnect the HDMI lead to the TV in order run the 10" display.
Similarly, if I want to run the TV, I pull out the low voltage 3.5mm plug from the small screen. Not what I wanted but it does cause less problems.

3) More Bad News. I have been trying to SSH into the HTPC (running 21.3) from my work machine running 21.1.

Usually it has meant running:

$sudo ufw allow 22 on both machines.

Yet in both directions I get connection refused.

Again on both machines, I ran:

$ sudo ufw disable
$ sudo ufw reset
$ sudo ufw allow 22 that returned:
Rules updated
Rules updated (v6)

but,

$ sudo ssh alan@192.168.1.5 [sudo] password for alan:
ssh: connect to host 192.168.1.5 port 22: Connection refused

I decided to try to ssh to another nerworked machine 192.168.1.66.
That returned:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ED25519 key sent by the remote host is
SHA256:+LnRj6UPz3fkZ1V85iHJq430xR98wVkf9pb/GoecWHI.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending ED25519 key in /root/.ssh/known_hosts:1
remove with:
ssh-keygen -f "/root/.ssh/known_hosts" -R "192.168.1.66"
Host key for 192.168.1.66 has changed and you have requested strict checking.
Host key verification failed.

So:
$ sudo ssh-keygen -f "/root/.ssh/known_hosts" -R "192.168.1.66"
After I confirmed that i wished to continue, I was able ssh to it without trouble.
It too has Linux Mint 21.1

When I tried to ssh into the HTPC (Mint 21.3) connection was refused.

I conclude that there is dsomething about 21.3 that is giving me grief.

--
Linux Mint 21.1 kernel version 5.15.0-91-generic Cinnamon 5.6.8
AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda

On Sat, 13 Jan 2024 14:43:04 +0000
pinnerite <pinnerite@gmail.com> wrote:

> On Fri, 12 Jan 2024 05:34:42 -0500
> Paul <nospam@needed.invalid> wrote:
>
> > On 1/11/2024 3:47 PM, Gordon wrote:
> > > On 2024-01-11, Paul <nospam@needed.invalid> wrote:
> > >> On 1/11/2024 8:36 AM, pinnerite wrote:
> > >>> I have just recovered control of my HTPC ;
> > >>> It has two HDMI sockets at the rear.
> > >>> One is connected by a long lead to a widescreen TV.
> > >>> The second is connected to a 10 inch monitor sittig on top.
> > >>>
> > >>> However!
> > >>>
> > >>> Cinnamon is treating them as two adjacent screens.
> > >>> I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.
> > >>>
> > >>> I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.
> > >>>
> > >>> The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
> > >>> This is rapidly becoming a hobby again!
> > >>>
> > >>> Alan
> > >>>
> > >>>
> > >>
> > >> The keyword might be "Mirror".
> > >>
> > >> An alternate alignment is "Span".
> > >>
> > >> When you operate a laptop and use the hotkey,
> > >> these might be modes just about any OS provides.
> > >> The hotkey toggles through all the modes,
> > >> panel, external, panel+external mirror, panel+external span .
> > >>
> > >> It is desktops, where you don't have the hotkey
> > >> (and presumably some little ACPI gizmo is missing).
> > >>
> > >> In any case, look for "Mirror" and see what you can find.
> > >>
> > >> Paul
> > >
> > > Look under Display from the start menu, which is under system settings.
> > >
> > > In/under Desktop, from main menu there us an option to Show icons on all
> > > desktops.
> > >
> >
> > I have a suspicion that refers to desktop icons in the upper part of the display.
> >
> > Window icons in the panel (Taskbar), don't seem to be interested in
> > spreading across two monitors, any time soon. The "traditional desktop"
> > is missing from the Welcome Screen, and playing with Add Panel or Applet
> > settings is a waste of time. The notion of "Linking" that the Display control panel
> > refers to, is not any notion of Linking I'm aware of. The monitors exist
> > in a 2D plane, and you can orient the monitors with respect to one another.
> > I don't know what the word "link" exactly has to do with it. Link seems
> > to mean "Hey, we aren't Mirroring right now".
> >
> > The hardware, there is two generations of hardware spanning support.
> > But it requires, as a general rule, identical monitors. You can connect
> > three 1920x1080 monitors and the hardware would treat that as a "5760x1080 surface".
> > That's the hardware spanning support. And if there was some way to do that,
> > then the Display control panel would be fooled into thinking it was
> > working with just one monitor (5760x1080). And all the decorations
> > would behave themselves.
> >
> > Attempting to "Add Panel" on my setup, to the second monitor,
> > just caused the panel on the first monitor to move to the
> > second monitor. This is not the notion of "Add" I would expect.
> > It's "Move" that it is doing.
> >
> > Paul
>
> Update:
>
> 1. Good news. When the TV is set for HDMI input and I run anything from Mythtv, any accompanying audo does come through the sound-bar. It always worried me that it might not.
>
> 2) Bad News. Selecting "Mirror" from Display caused the system to completely cut off the second screen and it took quite a while to get it back.
> It looks like I have to disconnect the HDMI lead to the TV in order run the 10" display.
> Similarly, if I want to run the TV, I pull out the low voltage 3.5mm plug from the small screen. Not what I wanted but it does cause less problems.

Even that didn't work earlier. It is terribly erratic.
> 3) More Bad News. I have been trying to SSH into the HTPC (running 21.3) from my work machine running 21.1.
>
This is resolved. I did not have ssh installed. (Idiot).
I must have forgotten to do so after updating following a
move.
>
>
>
>
>
>
> --
> Linux Mint 21.1 kernel version 5.15.0-91-generic Cinnamon 5.6.8
> AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda

--
Linux Mint 21.1 kernel version 5.15.0-91-generic Cinnamon 5.6.8
AMD Phenom II x4 955 CPU 16Gb Dram 2TB Barracuda

On 1/13/2024 9:43 AM, pinnerite wrote:
> On Fri, 12 Jan 2024 05:34:42 -0500
> Paul <nospam@needed.invalid> wrote:
>
>> On 1/11/2024 3:47 PM, Gordon wrote:
>>> On 2024-01-11, Paul <nospam@needed.invalid> wrote:
>>>> On 1/11/2024 8:36 AM, pinnerite wrote:
>>>>> I have just recovered control of my HTPC ;
>>>>> It has two HDMI sockets at the rear.
>>>>> One is connected by a long lead to a widescreen TV.
>>>>> The second is connected to a 10 inch monitor sittig on top.
>>>>>
>>>>> However!
>>>>>
>>>>> Cinnamon is treating them as two adjacent screens.
>>>>> I had hope that I could get them to work as showing the same image when the TV was switched to HDMI whereas although theY show the same background only one shows the taskbar (lower panel) and desktop icons.
>>>>>
>>>>> I have a feeling that I once managed to get the desktop icons and bottom panel duplicated on a second screen but i cannot remember how to do it.
>>>>>
>>>>> The system is not totally stable yet. I disconnected the HDMI cable from the 10 inch screen earlier and when I powered up the TV wouldn't even offer an HDMI connection!
>>>>> This is rapidly becoming a hobby again!
>>>>>
>>>>> Alan
>>>>>
>>>>>
>>>>
>>>> The keyword might be "Mirror".
>>>>
>>>> An alternate alignment is "Span".
>>>>
>>>> When you operate a laptop and use the hotkey,
>>>> these might be modes just about any OS provides.
>>>> The hotkey toggles through all the modes,
>>>> panel, external, panel+external mirror, panel+external span .
>>>>
>>>> It is desktops, where you don't have the hotkey
>>>> (and presumably some little ACPI gizmo is missing).
>>>>
>>>> In any case, look for "Mirror" and see what you can find.
>>>>
>>>> Paul
>>>
>>> Look under Display from the start menu, which is under system settings.
>>>
>>> In/under Desktop, from main menu there us an option to Show icons on all
>>> desktops.
>>>
>>
>> I have a suspicion that refers to desktop icons in the upper part of the display.
>>
>> Window icons in the panel (Taskbar), don't seem to be interested in
>> spreading across two monitors, any time soon. The "traditional desktop"
>> is missing from the Welcome Screen, and playing with Add Panel or Applet
>> settings is a waste of time. The notion of "Linking" that the Display control panel
>> refers to, is not any notion of Linking I'm aware of. The monitors exist
>> in a 2D plane, and you can orient the monitors with respect to one another.
>> I don't know what the word "link" exactly has to do with it. Link seems
>> to mean "Hey, we aren't Mirroring right now".
>>
>> The hardware, there is two generations of hardware spanning support.
>> But it requires, as a general rule, identical monitors. You can connect
>> three 1920x1080 monitors and the hardware would treat that as a "5760x1080 surface".
>> That's the hardware spanning support. And if there was some way to do that,
>> then the Display control panel would be fooled into thinking it was
>> working with just one monitor (5760x1080). And all the decorations
>> would behave themselves.
>>
>> Attempting to "Add Panel" on my setup, to the second monitor,
>> just caused the panel on the first monitor to move to the
>> second monitor. This is not the notion of "Add" I would expect.
>> It's "Move" that it is doing.
>>
>> Paul
>
> Update:
>
> 1. Good news. When the TV is set for HDMI input and I run anything from Mythtv, any accompanying audo does come through the sound-bar. It always worried me that it might not.
>
> 2) Bad News. Selecting "Mirror" from Display caused the system to completely cut off the second screen and it took quite a while to get it back.
> It looks like I have to disconnect the HDMI lead to the TV in order run the 10" display.
> Similarly, if I want to run the TV, I pull out the low voltage 3.5mm plug from the small screen. Not what I wanted but it does cause less problems.
>
> 3) More Bad News. I have been trying to SSH into the HTPC (running 21.3) from my work machine running 21.1.
>
> Usually it has meant running:
>
> $sudo ufw allow 22 on both machines.
>
> Yet in both directions I get connection refused.
>
> Again on both machines, I ran:
>
> $ sudo ufw disable
> $ sudo ufw reset
> $ sudo ufw allow 22 that returned:
> Rules updated
> Rules updated (v6)
>
> but,
>
> $ sudo ssh alan@192.168.1.5 [sudo] password for alan:
> ssh: connect to host 192.168.1.5 port 22: Connection refused
>
> I decided to try to ssh to another nerworked machine 192.168.1.66.
> That returned:
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
> @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
> IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
> Someone could be eavesdropping on you right now (man-in-the-middle attack)!
> It is also possible that a host key has just been changed.
> The fingerprint for the ED25519 key sent by the remote host is
> SHA256:+LnRj6UPz3fkZ1V85iHJq430xR98wVkf9pb/GoecWHI.
> Please contact your system administrator.
> Add correct host key in /root/.ssh/known_hosts to get rid of this message.
> Offending ED25519 key in /root/.ssh/known_hosts:1
> remove with:
> ssh-keygen -f "/root/.ssh/known_hosts" -R "192.168.1.66"
> Host key for 192.168.1.66 has changed and you have requested strict checking.
> Host key verification failed.
>
> So:
> $ sudo ssh-keygen -f "/root/.ssh/known_hosts" -R "192.168.1.66"
> After I confirmed that i wished to continue, I was able ssh to it without trouble.
> It too has Linux Mint 21.1
>
> When I tried to ssh into the HTPC (Mint 21.3) connection was refused.
>
> I conclude that there is dsomething about 21.3 that is giving me grief.

TV sets have a couple responses they can make.

A specific port on the TV, is "PC compatible". You should
be using this one, while Mirror testing. There might be a
different notation near the port, as a hint it is the single
PC port on the TV. It will operate with 640x480, 1024x768,
you know, the usual PC stuff. Mirroring the tiny display,
with the TV scalable port, should result in matching images
on the two devices. You will be able to tell, by the appearance,
this is a bad idea (does not make the best usage of the TV set).

If the TV set is 1920x1080 native, then the best ten inch panel
to play along as a mate, is a 1920x1080 one, because more options
are going to look good (such as mirroring). You can always
link or span the two (mismatched) displays. Some multimedia softwares will
put the "ten foot display" on the HD panel.

The other HDMI TV ports can be "HD/SD type". The TV set is OK if you
use 1920x1080 or some SD res, something like that (I don't have such
equipment to test). Attempts to feed some other resolution
will fail with a black screen. Some values associated with SD are shown
here, but I don't know right off hand, what the TV expects. Usually,
the detailed PDF that comes with some Tv sets, has precise details
on what each HDMI port supports. The purpose of an HD/SD port,
is for connection of TV Set-top-boxes, or for a BluRay set top player machine.
If your TV is 4K, then a few more "multimedia" resolutions might be
included.

https://en.wikipedia.org/wiki/Standard-definition_television

At one time, TV sets may have used a VGA port for the "PC one".
Today, they nominate one of the HDMI ones for PC usage. And
a scaler translates sub-native resolutions into something the
panel in the TV set can use.

Good TV sets have excellent manuals, with tables of what
the TV supports. Occasionally, there is even a list of movie
formats that work on the USB port on the TV set (play movies off
USB stick).

Paul