Created attachment 258057 [details] dmesg After upgrading from kernel 4.11 to 4.12, I cannot use discrete video card mode for my Thinkpad P50 with GM107 GPU (Quandro M1000M). It will boot into blank screen for the laptop screen. In the external screen, the console will display some very weird font. Startx will result in blank screen again. I tried dmesg and found error message. Full dmesg is attached. [ 2.897407] nouveau 0000:01:00.0: NVIDIA GM107 (117310a2) [ 3.242850] nouveau 0000:01:00.0: eDP-1: EDID is invalid: [ 3.242851] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242852] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242852] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242852] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242853] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242853] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242854] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 3.242854] [00] BAD 00 00 00 00 00 00 00 00 00 00 00 00 00 ff 00 ff [ 3.242855] nouveau 0000:01:00.0: DRM: DDC responded, but no EDID for eDP-1 Downgrading to kernel 4.11.5, the GPU in discrete mode works fine. It doesn't have the EDID invalid error. The error persists even on the latest 4.12.8. The hybrid mode GPU works fine for both kernels though.
You need https://github.com/skeggsb/linux/commit/13a86519202c5d119d83640d6f781f3181205d2c (which is in 4.13-rcN)
Yes, verified working on 4.13. Closing this bug!