I want to know if my notebook GPU is well configured with the maximum resolution. I read this question to know the current monitor resolution:
$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maxiumum 8192 x 8192
It shows that maximum is 8192 x 8192 (is it monitor or GPU maximum resolution). The GPU is a GM107M [GeForce GTX 960M] [10DE:139B]. Its website shows it supports 4K.
How can I know if it is configured with the maximum resolution?
Your GPU supports up to 8192x8192 resolution, but the monitor supports up to 1920x1080 as you can see.
If you connect an external monitor, you'll be able to get a higher resolution.
You cannot set the video display resolution beyond what your current monitor supports, though it is possible to set a lower value.
Typing xrandr in your terminal will show you an output as below
Screen 0: minimum 320 x 320, current 1920 x 1080, maximum 8192 x 8192
minimum 320 x 320 - shows you the minimum,
current 1920 x 1080 - shows your current screen resolution.
maximum 8192 x 8192 - the maximum resolution that your gpu supports.
If you want to achieve higher results you will have to connect an external monitor with a higher resolution.
Also make sure your connection interface supports the higher resolution you want to use as that may also limit you.
You can learn the native resolution of your LCD display by using the edid-decode utility to decode the monitor's EDID data.
sudo apt install edid-decode
The native resolution (i.e. exactly how many pixels the display actually has) is important because, first, it is not possible to select a higher resolution, and second, if you select a lower resolution the display will either place black bars around the displayed image (which looks bad) or try to interpolate pixels to stretch the image (which looks even worse).
To use it, you will need to get the paths for your display's EDID, which are exposed in sysfs. You can use find to find them. For example:
$ find /sys/devices -name edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-1/edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-2/edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-2/edid
/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-1/edid
One will be listed for every display port the system thinks it has (even some that don't physically exist). For your laptop, the built in display will usually be eDP-1. An external monitor may be connected to an HDMI port or a DP port, depending on what your laptop's ports actually are.
Run edid-decode on each of these to decode their data, and look in the Block 0, Base EDID: section under the Basic Display Parameters & Features: subsection for a message about the First detailed timing. For example, from my laptop's screen:
$ edid-decode /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/edid
....
First detailed timing includes the native pixel format and preferred refresh rate
Or, from my external monitor:
$ edid-decode /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-HDMI-A-1/edid
....
First detailed timing is preferred timing
You can then look at the Detailed Timing Descriptors: in the same Block to see the native resolution. For example, my laptop's screen shows:
Detailed Timing Descriptors:
DTD 1: 1920x1080 60.056 Hz 16:9 67.143 kHz 141.000 MHz (344 mm x 193 mm)
My external monitor shows:
Detailed Timing Descriptors:
DTD 1: 1920x1080 60.000 Hz 16:9 67.500 kHz 148.500 MHz (476 mm x 268 mm)
My external monitor also has a Block 1, CTA-861 Extension Block: with additional Detailed Timing Descriptors listed. You can ignore such a block for this purpose.
If there is nothing connected to the port, you will just get an error. For example:
$ edid-decode /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-1/edid
EDID extract of '/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-DP-1/edid' failed
