I have an ASUS laptop P2451FA. It has a USB-C port, HDMI port, and VGA port. Most of the time, I use the HDMI port to extend my Laptop monitor.
Recently I bought a portable monitor with a USB-C connector and I want that as my third monitor. This is the result of xrandr when using only HDMI
Screen 0: minimum 320 x 200, current 2732 x 768, maximum 16384 x 16384
eDP-1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 309mm x 173mm
1366x768 60.00*+
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
700x525 59.98
800x450 59.95 59.82
640x512 60.02
700x450 59.96 59.88
640x480 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-1 connected 1366x768+1366+0 (normal left inverted right x axis y axis) 411mm x 229mm
1366x768 59.79*+ 75.00
1280x1024 60.02
1280x768 59.87
1280x720 60.00
1024x768 75.03 70.07 60.00
800x600 72.19 75.00 60.32
640x480 75.00 72.81 59.94
720x400 70.08
and when plugging the portable monitor
Screen 0: minimum 320 x 200, current 2646 x 768, maximum 16384 x 16384
eDP-1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 309mm x 173mm
1366x768 60.00*+
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88
864x486 59.92 59.57
700x525 59.98
800x450 59.95 59.82
640x512 60.02
700x450 59.96 59.88
640x480 60.00 59.94
720x405 59.51 58.99
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83 59.84 59.32
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32 56.34
432x243 59.92 59.57
320x240 60.05
360x202 59.51 59.13
320x180 59.84 59.32
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected 1280x720+1366+24 (normal left inverted right x axis y axis) 344mm x 195mm
1920x1080 60.00 + 50.00 59.94 30.00 29.97
1280x720 60.00* 50.00 30.00 59.94 29.97
1024x768 60.00
1440x480 60.00 59.94
800x600 60.32
720x480 60.00 59.94
640x480 60.00 59.94
HDMI-1 connected (normal left inverted right x axis y axis)
1368x768 59.88
1280x800 59.81
1280x720 59.86
1024x768 60.00
1024x576 59.90
960x540 59.63
800x600 60.32
800x450 59.82
700x450 59.88
640x480 59.94
684x384 59.88 59.85
640x400 59.88 59.98
640x360 59.86 59.83
512x384 60.00
512x288 60.00 59.92
480x270 59.63 59.82
400x300 60.32
320x240 60.05
it is detected but shows a blank screen in both (the HDMI and the portable monitor (DP-2)). How can I configure my laptop so the HDMI and the portable monitor can be used simultaneously?
According to this your laptop has only a built-in Intel UHD Graphics that can drive a monitor via hdmi or vga. Most mobile devices that can drive a monitor via usb-c have the DP port hard-wired to the dedicated graphics card, so check your manual if your device actually supports monitors via usb-c.
In order to not have to guess your exact hardware specs better show us the output of: inxi -Fazy
DP-2 is on bottom right, but on the screenshot it is top left.
HDMI-1 is on top left, but on the screenshot it is top right.
Does it even save the configuration?
Also only connections are active. HDMI is inactive.
However, I’m concerned that HDMI and USB-C share a cable connection. Internally there are not two connections, but one. If it was a second DisplayPort that would work, but USB-C? I doubt that. The USB-C and HDMI port are next to each other, which gives the impression that they are connected to each other.
That is different.
DP-2 is on bottom right, but on the screenshot it is top left.
HDMI-1 is on top left, but on the screenshot it is top right.
Does it even save the configuration?
No, it is not save the configuration.
However, I’m concerned that HDMI and USB-C share a cable connection. Internally there are not two connections, but one. If it was a second DisplayPort that would work, but USB-C? I doubt that. The USB-C and HDMI port are next to each other, which gives the impression that they are connected to each other.
I think this is the cause, the USB-C and HDMI are share a cable connection which is not two connection.
Regarding this condition, my laptop also has a VGA port, which rarely used. Haven’t tried yet with this port.
