### 🔄 Update – Additional trigger identified (DPMS)

After further testing, I identified a second trigger for the issue, not
limited to suspend/resume.

#### Reproduction (new scenario):

1. Resume system normally (works)
2. Let system go idle until screen turns off (DPMS)
3. Wake system via keyboard/mouse

#### Result:

* Display does not recover properly
* Black screen or corrupted session
* Behavior similar to suspend/resume failure

#### Key observation:

Disabling the phantom output (DVI-D-1) immediately restores the display.

#### Workarounds:

* `xrandr --output DVI-D-1 --off`
* Forcing HDMI-A-0 as primary
* Disabling automatic screen-off avoids the issue

#### Interpretation:

This suggests the issue affects **display reinitialization after power
transitions**, not just suspend.

Likely areas involved:

* EDID re-read
* HDMI link training
* atomic modeset restore
* DC state restore

This reinforces that the regression is likely timing/order related
rather than tied to a specific subsystem change.

More logs can be provided if needed.

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https://bugs.launchpad.net/bugs/2142389

Title:
  amdgpu (R9 380) fails to resume from suspend (deep sleep) – black
  screen, requires hard reboot

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