KBL- No signal on Samsung 4K TV when running Ubuntu 20.04
Hi
We encountered display failure on Samsung 4K TV with KBL platfrom (embedded with PS175 DP2HDMI converter)
The monitor shows ok in Bios and kernel early booting procedure, it lost signal after i915 driver installed.
It is similar as #2755 (closed) .
The issue can't be fixed by the workaround fix of #2755 (closed) ( force set max_bpp to 24)
The issue only happen with 4K resolution
BAD Case:
The issue reproduced on
- Ubunt18.04.4 (kernel 5.4) ,
- Ubuntu20.04(kernel 5.8) ,
- Ubuntu20.10 (drm-tip master)
- CIV Android11 master baremetal(kernel 5.10)
Good Case:
It is NOT reproduced on
- ubuntu18.10 (kernel 4.18) ,
- Celadon Android 9 Baremetal(kernel 4.19)
Note： The hardware tested is called ClassHub designed by Mythware with KabyLake , it has an embedded PS175 to convert DP 2 HDMI. It is the same hardware as mentioned in #2755 (closed)
Here are some logs ,
Here is the edid of Samsung TV
Edited by whf839