External monitor resolution

[Franz]

On Qubes 3.2 had to add an External monitor because my Lenovo x230 laptop display started flickering and slowing down. But the resolution on the external monitor is wrong. What appears on screen is correctly high, but too large to fit into the screen.

Running xrandr gives the output on the enclosed photo. From that I imagine  that the resolution of the external monitor should be changed to 1366x768.

But how do I do that? I spent a couple hours reading many old threads, but they imply a knowledge I do not have, só cannot figure out. Also am afraid of doing something wrong and loosing access to my computer.

Any idea?

[unman]

I don't know what was in the photo.
But you should be able to access these settings under the Qubes menu,
System Settings, Display entry.

[Franz]

Thanks Unman,

I found it and it is pretty easy, but maximum resolution option for the external monitor is 1024x768. Does this mean that for some reason it is impossible to set 1366x768?

--
You received this message because you are subscribed to the Google Groups "qubes-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscribe@googlegroups.com.
To post to this group, send email to qubes...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/20180924161109.d27vv63u7y55arvl%40thirdeyesecurity.org.
For more options, visit https://groups.google.com/d/optout.

[Franz]

On Mon, Sep 24, 2018 at 2:38 PM, Franz <169...@gmail.com> wrote:

On Mon, Sep 24, 2018 at 1:11 PM, unman <un...@thirdeyesecurity.org> wrote:

On Mon, Sep 24, 2018 at 01:02:50PM -0300, Franz wrote:
> On Qubes 3.2 had to add an External monitor because my Lenovo x230 laptop
> display started flickering and slowing down. But the resolution on the
> external monitor is wrong. What appears on screen is correctly high, but
> too large to fit into the screen.
>
> Running xrandr gives the output on the enclosed photo. From that I imagine
> that the resolution of the external monitor should be changed to 1366x768.
>
> But how do I do that? I spent a couple hours reading many old threads, but
> they imply a knowledge I do not have, só cannot figure out. Also am afraid
> of doing something wrong and loosing access to my computer.
>
> Any idea?

I don't know what was in the photo.
But you should be able to access these settings under the Qubes menu,
System Settings, Display entry.

Thanks Unman,

I found it and it is pretty easy, but maximum resolution option for the external monitor is 1024x768. Does this mean that for some reason it is impossible to set 1366x768?

Here are some old comments from Marek that suggest that something can be done, but they are somehow abstracted for me to be able to follow:

"I'm not sure if the driver loaded at disk password prompt time is able
to set higher resolution. But you can try with "video=" kernel
parameter.

For one-time test, you can edit kernel command line in grub (press "e"
on the entry, go to "module /vmlinuz..." line and add the option at the
end, then boot with ctrl-x). You can start with something like
video=1920x1080 (or whatever resolution you want). Details about option
syntax in kernel documentation[1].

When you find the right value, you need to edit /etc/default/grub
(GRUB_CMDLINE_LINUX line) in dom0 to make the change permanent. After
editing this file, you need to regenerate actual grub configuration:
grub2-mkconfig -o /boot/grub2/grub.cfg

[1] https://www.kernel.org/doc/Documentation/fb/modedb.txt"

[Franz]

On Mon, Sep 24, 2018 at 5:30 PM, Franz <169...@gmail.com> wrote:

On Mon, Sep 24, 2018 at 2:38 PM, Franz <169...@gmail.com> wrote:

On Mon, Sep 24, 2018 at 1:11 PM, unman <un...@thirdeyesecurity.org> wrote:

On Mon, Sep 24, 2018 at 01:02:50PM -0300, Franz wrote:
> On Qubes 3.2 had to add an External monitor because my Lenovo x230 laptop
> display started flickering and slowing down. But the resolution on the
> external monitor is wrong. What appears on screen is correctly high, but
> too large to fit into the screen.
>
> Running xrandr gives the output on the enclosed photo. From that I imagine
> that the resolution of the external monitor should be changed to 1366x768.
>
> But how do I do that? I spent a couple hours reading many old threads, but
> they imply a knowledge I do not have, só cannot figure out. Also am afraid
> of doing something wrong and loosing access to my computer.
>
> Any idea?

I don't know what was in the photo.
But you should be able to access these settings under the Qubes menu,
System Settings, Display entry.

Your System setting works Unman, i had to set all three flags:

1. external display is in Use

2. External display is primary

3. Displays are in mirror mode

So what is shown on the laptop is a bit smaller than the screen, but the external display is perfect.

I understand that the Lenovo x230 does not have the power to properly set the two displays each with the correct resolution, but in mirror mode, they are exactly the same and it works.

Many thanks Unman.

[Holger Levsen]

On Mon, Sep 24, 2018 at 06:52:30PM -0300, Franz wrote:
> I understand that the Lenovo x230 does not have the power to properly set
> the two displays each with the correct resolution, but in mirror mode, they
> are exactly the same and it works.

I use an x230 here with an external 4k display and it works nicely, with
or without using the internal display as well. (using the mini-displayport
output, not VGA.)

As a start, I'd recommend to run "xrandr --auto" in dom0.


--
cheers,
Holger

-------------------------------------------------------------------------------
holger@(debian|reproducible-builds|layer-acht).org
PGP fingerprint: B8BF 5413 7B09 D35C F026 FE9D 091A B856 069A AA1C

[Franz]

On Tue, Sep 25, 2018 at 7:49 AM, Holger Levsen <hol...@layer-acht.org> wrote:

On Mon, Sep 24, 2018 at 06:52:30PM -0300, Franz wrote:
> I understand that the Lenovo x230 does not have the power to properly set
> the two displays each with the correct resolution, but in mirror mode, they
> are exactly the same and it works.

I use an x230 here with an external 4k display and it works nicely, with
or without using the internal display as well. (using the mini-displayport
output, not VGA.)

As a start, I'd recommend to run "xrandr --auto" in dom0.

Thanks Holger,

my external monitor only has a VGA port so I do not know how to connect it to the mini-display port.

Using the VGA connection it works only as mirror. If I try to keep the laptop screen at its original resolution 1366x768, and the external screen at 1024x768, then the external screen shows only  the Qubes logo (you know the big white Q with the same Q broken into pieces) and if I move the mouse to the right, over the border of the laptop screen, it goes into the external screen. So it seems the laptop screen and the external screen show different things. But the external screen with the Qubes logo is useless.