Potential Bug (?) related to Tablet HDMI Display settings that don’t work unless you edit the EDID file of the display tablet

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Hello! I noticed lately that my xp-pen’s tablet color quality wasn’t on-par with the one on windows 11 so I did a bit of digging and found that the display settings related to RGB range and sRGB color intensity didn’t work or are less effective unless you copy the EDID file of the tablet and set YCbCr 4:2:2 and 4:4:4 at 0, set a firmware folder with the copy of the edid, edit the grub and mkinitcpio.conf, reload both and restart. Now I don’t know if this is a bug or something else related to linux and xp-pen’s lack of support or even HDMI shenanigans but if someone has similar troubles here’s the process of fixing this.

  1. open the location of the xp-pen’s edid file which is the HDMI drm/edid location (or any potential other connection type being DP or type-c but mine’s was HDMI) mine was “/sys/devices/pci0000:00/0000:00:03.1/0000:07:00.0/0000:08:00.0/0000:09:00.0/drm/card1/card1-HDMI-A-1/”
  2. Copy the EDID file and copy paste it in a new folder called “edid” in /usr/lib/firmware so the location youre going to be pasting the edid file is “/usr/lib/firmware/edid/” note to create the edid folder and copy pasting the file you need to be doing this with administration rights.
  3. Now open the EDID file we copied with wxEDID and find “CEA/CTA-861 header” on it youre going to set both YCbCr 4:2:2 and 4:4:4 at 0 and save the edid as edid.bin on the firmware/edid folder. This will create a new edid.bin file so we can delete the old edid file we copied and pasted on the firmware/edid folder. this .bin file we can name whatever we want but this name must be used for the next steps so I recommend naming it “edidrgb.bin”.
  4. if youre using grub, on konsole type “sudo nano /etc/default/grub” (this will vary depending on how you installed arch or anything else) and put
    drm.edid_firmware=HDMI-A-1:edid/edidrgb.bin so now it will look like
    GRUB_CMDLINE_LINUX_DEFAULT=“loglevel=3 quiet drm.edid_firmware=HDMI-A-1:edid/edidrgb.bin”
  5. Now do “sudo grub-mkconfig -o /boot/grub/grub.cfg” to reload the grub config
  6. next do “sudo nano /etc/mkinitcpio.conf” , find # FILES and on FILES=() put the location of the “/usr/lib/firmware/edid/” so “FILES=(/usr/lib/firmware/edid/edidrgb.bin)”
  7. sudo mkinitcpio -p linux to reload.
  8. Now restart and everything should work now with RGB range and sRGB color intensity working more noticeably than before.

Now if you ask me what is causing this issue, I’d image being the HDMI more than lack of support from xp-pen.

For context im on Arch, Plasma 6.3.5 and using an Amd GPU (rx6700xt).