[Bug 107679] New: i915 display link training after suspend/resume

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=107679

            Bug ID: 107679
           Summary: i915 display link training after suspend/resume
           Product: DRI
           Version: unspecified
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: freedesktop at delyan.me
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org

Created attachment 141272
  --> https://bugs.freedesktop.org/attachment.cgi?id=141272&action=edit
kernel messages while system is trying to turn on the two attached displays

System: Dell XPS 9570 (Coffee Lake i7-8750H)
Kernel: 4.18.1-1.vanilla.knurd.1.fc28.x86_64
Kernel params: i915.enable_fbc=1 i915.enable_psr=1 i915.enable_guc=3

GuC/HuC versions:
kernel: [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4)
kernel: [drm] HuC: Loaded firmware i915/kbl_huc_ver02_00_1810.bin (version 2.0)
kernel: [drm] GuC: Loaded firmware i915/kbl_guc_ver9_39.bin (version 9.39)


Steps:
1. Boot system. 
2. Connect to Dell WD-15 dock (Synaptics VMM3332 chip inside).
3. Observe X11 session correctly modesetting two Dell displays connected to the
dock to 1920x1200. Laptop display gets disabled, per configuration.
4. Suspend system.
5. Resume system.

Expected behavior:
Both external displays wake up and modeset correctly.

Actual behavior:
Neither display wakes up, laptop display is still on, system is unresponsive
except for mouse movement.

Attached is the relevant kernel log from just after the resume.

I have also confirmed this bug on vanilla 4.19-rc0.

Please let me know if there's anything further I can provide, I can
consistently reproduce this issue.

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