ChangingEDIDInQemu

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edid retrieve

Install edid related packages:

$ sudo apt install -y edid-decode read-edid

Find the edid in /sys:

$ sudo find /sys | grep edid
/sys/kernel/debug/dri/0/Virtual-1/edid_override
/sys/devices/pci0000:00/0000:00:01.0/drm/card0/card0-Virtual-1/edid
/sys/module/drm_kms_helper/parameters/edid_firmware
/sys/module/drm/parameters/edid_firmware
/sys/module/drm/parameters/edid_fixup

The /sys/devices/pci0000:00/0000:00:01.0/drm/card0/card0-Virtual-1/edid file is your edid file, transfer it to windows machine.

edid modification

Using AW EDID Editor for editing the edid file:

Remove the items you won’t preserve:

Modified items:

Using the new edid file

Edit the grub options:

$ sudo vim /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet drm.edid_firmware=Virtual-1:edid/edidno1080.bin"

Add initram-tools hooks(Added scripts in kmod - the hacking way):

$ cat /usr/share/initramfs-tools/hooks/kmod 

......
......
......
# hacking for edid
mkdir -p ${DESTDIR}/lib/firmware/edid
mkdir -p ${DESTDIR}/usr/lib/firmware/edid

cp /lib/firmware/edid/edidno4k.bin ${DESTDIR}/lib/firmware/edid/
cp /lib/firmware/edid/edidno1080.bin ${DESTDIR}/lib/firmware/edid/
cp /usr/lib/firmware/edid/edidno4k.bin ${DESTDIR}/usr/lib/firmware/edid/
cp /usr/lib/firmware/edid/edidno1080.bin ${DESTDIR}/usr/lib/firmware/edid/

Update the kernel and initramfs:

$ sudo update-grub2
$ sudo update-initramfs -u -k all

Effects

edid-decode result:

root@idvrescue:/home/hhh# edid-decode < /sys/devices/pci0000:00/0000:00:01.0/drm/card0/card0-Virtual-1/edid
......
hecksum: 0x47

----------------

Block 1, CTA-861 Extension Block:
  Revision: 3
  Native detailed modes: 0
  Video Data Block:
    VIC  31:  1920x1080   50.000000 Hz  16:9     56.250 kHz    148.500000 MHz
Checksum: 0x95

Dmesg output:

$ sudo dmesg | grep edid
[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-18-amd64 root=UUID=f1fa5be7-1a17-46e3-ac0d-ab936027037e ro quiet drm.edid_firmware=Virtual-1:edid/edidno1080.bin
[    0.014022] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-18-amd64 root=UUID=f1fa5be7-1a17-46e3-ac0d-ab936027037e ro quiet drm.edid_firmware=Virtual-1:edid/edidno1080.bin
[    0.635432] [drm] features: -virgl +edid -resource_blob -host_visible
[    0.635877] platform Virtual-1: firmware: direct-loading firmware edid/edidno1080.bin
[    0.635885] [drm] Got external EDID base block and 1 extension from "edid/edidno1080.bin" for connector "Virtual-1"