Forced EDID is ignored

Submitted by Heiko Lechner

Assigned to Default DRI bug account

Link to original bug (#110423)

Description

Created attachment 143968
output from edid-decode from hacked EDID file

I have a tv that does not handle YCbCr properly but advertises it in his EDID. So I have to force Full RGB over HDMI because it seems that my RX 570 uses YCbCr by default (maybe because of the HDMI connection?).
There is no switch to force Full RGB so I downloaded the EDID with get-edid using i2c and hacked it to disable the advertisement of YcbCr. I copied it to the initrd and force loaded it via drm.edid_firmware=edid/PhilipsFTV.bin.
It works:
[ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.0.0-trunk-amd64 root=UUID=1c91ef55-0cf6-4694-bd2a-29aeb6492b3b ro drm.edid_firmware=edid/PhilipsFTV.bin
[ 0.849967] platform HDMI-A-1: firmware: direct-loading firmware edid/PhilipsFTV.bin
[ 0.850055] [drm] Got external EDID base block and 1 extension from "edid/PhilipsFTV.bin" for connector "HDMI-A-1"

But the problems with my tv persist. So I think that the forced EDID is ignored by AMDGPU.

uname -a:
Linux Heimkino-PC 5.0.0-trunk-amd64 #1 (closed) SMP Debian 5.0.7-1~exp1 (2019-03-22) x86_64 GNU/Linux

Attachment 143968, "output from edid-decode from hacked EDID file":
Philips_FTV_hacked_human_readable.txt