Claude review: drm/msm/dp: Skip push_idle in atomic_disable if display is not powered on

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Commit message:** Well-written. It clearly explains the root cause (eDP with no panel → DPCD read failure → `ST_DISCONNECTED` → `atomic_enable` exits early → `power_on` stays false → `push_idle` writes to unpowered register → NoC error). Good.

**Code change:**

```c
+	if (!dp->power_on)
+		return;
+
 	msm_dp_ctrl_push_idle(msm_dp_display->ctrl);
```

**Correctness:** The guard is logically correct. If `power_on` is `false`, the link clocks are not enabled, so writing to `REG_DP_STATE_CTRL` via `msm_dp_ctrl_push_idle()` would access unpowered hardware. The check is consistent with the guard in `msm_dp_display_disable()` which does the same pattern (`if (!msm_dp_display->power_on) return 0;`).

**Minor concern — early return skips post_disable flow:** The `atomic_disable` → `atomic_post_disable` sequence means that even when we return early here, `msm_dp_bridge_atomic_post_disable()` will still be called. That function calls `msm_dp_display_disable()`, which has its own `power_on` guard, so the early return here is safe — `atomic_post_disable` won't crash either. The `pm_runtime_put_sync()` at the end of `atomic_post_disable` could be called without a matching `pm_runtime_get`, but looking at the enable path, `pm_runtime_get_sync` is called in `atomic_pre_enable`, which would also have been called before `atomic_post_disable` during the suspend teardown. So this should be balanced correctly.

**Nit — comment length:** The 3-line comment is fine for explaining a non-obvious guard, though it could be slightly more concise. This is a minor style preference and not a blocker.

**No other issues found.** The patch is minimal, well-scoped, and addresses a real crash. It could benefit from a `Fixes:` tag referencing the commit that introduced the unconditional `msm_dp_ctrl_push_idle()` call in `atomic_disable`, which would help stable backporting.

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