Bug 196733

Summary: GM107 video card displays blank screen after 4.12 update with error EDID checksum
Product: Drivers Reporter: Liberty (mrlhwliberty)
Component: Video(DRI - non Intel)Assignee: drivers_video-dri
Status: RESOLVED CODE_FIX    
Severity: normal CC: imirkin
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 4.12.8 Subsystem:
Regression: No Bisected commit-id:
Attachments: dmesg

Description Liberty 2017-08-22 23:39:40 UTC
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.
Comment 1 Ilia Mirkin 2017-08-22 23:45:27 UTC
You need

https://github.com/skeggsb/linux/commit/13a86519202c5d119d83640d6f781f3181205d2c

(which is in 4.13-rcN)
Comment 2 Liberty 2017-09-12 19:30:50 UTC
Yes, verified working on 4.13. Closing this bug!