How can I determine maximum supported display resolution?

Question

I have laptop with: Dual-Core Intel i5 CPU (https://ark.intel.com/content/www/us/en/ark/products/43544/intel-core-i5540m-processor-3m-cache-2-53-ghz.html)

and I would like to determine maximum supported display resolution (in order to connect external monitor)

am using HDMI to connect laptop(Dell Latitude E6410) to external monitor (benq GW2765 with native resolution 2560x1440)

At the moment only available max resolution in Settings in EOS is 1920x1080 and I want to change it to 2560x1440 (which is a native resolution for my LCD monitor)

but it is not shown as an option?

Want to see whether it is because it is not supported by laptop or can I change something in Elementary? I am running 6.1 Jolnir

UPDATE 1:

xrandr didn't work :-(

I wasn't able to add the display mode I wanted, but...

I learned how to use dual monitor with Elementary (very easy)

I have changed external monitor settings to scale 1:1 to avoid distortion caused by using non-native display

and now with my CAD application shared between two screens (see below) it is reasonably usable

I am now convinced that the limitation is my laptop rather than anything else

(I have checked what GPU is available on laptop, using lspci command)

VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)

so, it sounds like I am stuck with this one :-(

UPDATE 2: Well... I was WRONG :-)

it is possible to add another display resolution!

The trick is to run xrandr before doing anything else to establish which monitor/connection is called what (as you @Vlad have quite correctly pointed out and I have missed ...)

The result:

You can see that 2560x1440 is available to choose!

Resulting display still has black areas around it,

but it is definitely usable (especially when using both monitors)

This maybe related to the message I get when setting output of HDMI to new mode? (I don't like the word failed ??)

bambuko@LatitudeE641005543265:~$ xrandr --output HDMI-1 --mode 2560x1440_60.00
xrandr: Configure crtc 0 failed

Further confirmed by running:

bambuko@LatitudeE641005543265:~$ xrandr --listactivemonitors
Monitors: 2
 0: +*HDMI-1 1920/597x1080/336+0+0  HDMI-1
 1: +eDP-1 1280/303x800/190+320+1080  eDP-1

where it should be (if successful)

+HDMI-1 2560/***x1440/***+*+* HDMI-1

searching the web for xrandr: Configure crtc 0 failed

returns a lot, but none of it makes any sense to me yet...

bambuko@LatitudeE641005543265:~$ lspci -knn | grep -iA3 'vga\|3d\|display'
00:02.0 VGA compatible controller [0300]: Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 02)
    Subsystem: Dell Latitude E6410 [1028:040a]
    Kernel driver in use: i915
    Kernel modules: i915

for reference:

https://linux.die.net/man/1/xrandr

and

https://youtu.be/MWNpSgX6Eg0

and

https://askubuntu.com/questions/73007/cant-set-a-higher-screen-resolution-in-a-external-display-in-a-dell-mini-10v-la

Answer 1

We have a solution!

I've spent all day trying various suggestions from interweb (all failing),

until I came upon this:

https://unix.stackexchange.com/questions/599466/three-monitors-xrandr-configure-crtc-failed

I have experimented with various refresh rates instead of the typical 60Hz

50Hz still failed, 30Hz was outside the range (screen went black),

but with 40Hz it looks just perfect - here the view of 2560x1440 monitor with laptop screen below at 1280x800 working as one

This was achieved with following:

bambuko@LatitudeE641005543265:~$ cvt 2560 1440 40
# 2560x1440 39.96 Hz (CVT) hsync: 58.98 kHz; pclk: 201.00 MHz
Modeline "2560x1440_40.00"  201.00  2560 2720 2984 3408  1440 1443 1448 1476 -hsync +vsync