Re: xrandr 1600x900 (ThinkPad X220T VGA-port) becomes 1440x900 (Samsung SyncMaster S20A300B)

[Felix Miata <mrmazda@earthlink.net>]

riveravaldez composed on 2023-10-18 16:05 (UTC-0300):

> Hi everybody, I'm having a resolution issue trying to connect an
> external monitor to a laptop.
...
>
https://support.lenovo.com/us/en/solutions/pd015807-detailed-specifications-thinkpad-x220-tablet

That URL covers multiple configurations, so we can't know all that is relevant
from it.

Using DP instead of VGA would likely solve this if your display had a DP input. :p
VGA is analog. DP, HDMI, DVI are all digital. So is your CPU, GPU and software.
The conversion to analog from digital typically is worse than flawless.

That said, give us something to work from:

1-copy & paste input/output from
	inxi -GSaz
run from an GUI terminal.

2-pastebin Xorg.0.log from either /var/log/ or ~/.local/share/xorg/ and provide
its URL.

Below in file named /etc/X11/xorg.conf.d/50-monitor.conf could be part of a
solution, with more information the above request would supply.

Section "Monitor"
    Identifier "ExtMonitor"
	VendorName	"Samsung"
	ModelName	"S20A300B"
	HorizSync	30-83
	VertRefresh	56-76
	Option	"PreferredMode"	"1600x900"
EndSection

This is essentially the information that the EDID from the Samsung should be
supplying that X seems to be mishandling. The numbers for sync and ref are
estimates, simply copied from a 2012 20" Dell 1600x900 I have here. With only one
display it would be enough, but it needs to be assigned to the VGA port connection
via another file, /etc/X11/xorg.conf.d/50-device.conf. The following might be enough:

Section "Device"
    Identifier "ExtDevice"
	Option	"monitor-VGA-1"	"ExtMonitor"
EndSection

I've always been able to use files in /etc/X11/xorg.conf.d/ to manage unruly
displays rather than resorting to CVT or GTF for manual modeline generation. X
knows quite well how to generate appropriate modelines when it has the correct
specifications to work with. EDID is supposed to do that.
-- 
Evolution as taught in public schools is, like religion,
	based on faith, not based on science.

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata