size of display connected via HDMI was'nt automatically detected correctly (xUbuntu)

Question

I have xUbuntu 18.04.4 LTS (XFCE 4.12 + 4.15.0-111 Linux kernel) on the Dell Vostro 3360 laptop. When I connected the external display (Samsung SyncMaster T240) via VGA cable - all is good and I got such xrandr output:

xrandr -q
***
VGA-1 connected 1920x1200+1366+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+
***

But when I connected this one via HDMI cable the size of this display isn't detected correcltly (in the XFCE Display window it shows as Samsung 7") and I got such output:

***
xrandr -q
HDMI-1 connected 1920x1200+1366+0 (normal left inverted right x axis y axis) 160mm x 90mm
   1920x1200     59.95*+
***

Accordingly, some apps such as Viber or Caliber are displayed with "huge controls".

How I can fix this problem (desirable - not only for this display, but for HDMI-connections at all)?

UPDATED. for now looks like problem is in EDID-information that is sending by external-display via HDMI (and NO, xrandr --fbmm doesn't works...)

Answer 1

So, I solved my problem in such way:

• downloaded prepared EDID repository for existing displays (https://github.com/linuxhw/EDID/)
• found from there most appropriate model (by vendor + resolutions + screen size + frequency)
• changed content of edid-binary.file that I got previously via get-edid utility - to EDID-string from edid-file that I found
• assigned that new file as a parameter of Linux kernel (and added some debug information for dmesg) so I got in /etc/default/grub string GRUB_CMDLINE_LINUX_DEFAULT="drm.debug=14 log_buf_len=20M debug drm.edid_firmware=HDMI-A-1:edid/edid1.bin quiet splash" (and executed sudo update-grub then)
• well done :)