Claude review: drm/i915/dp: On AUX_CH tx timeout, wake up the sink

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

Patch Review

**Recursive AUX concern:**

```c
if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
    drm_dp_wake_sink(&intel_dp->aux);
    continue;
}
```

`drm_dp_wake_sink()` internally calls `drm_dp_dpcd_readb()` and `drm_dp_dpcd_writeb()`, which will call back into `intel_dp_aux_xfer()`. This is called inside the retry loop (up to 5 tries × number of clock dividers). Each invocation of `drm_dp_wake_sink` can itself do up to 6 retries with 1ms sleeps plus additional DPCD writes. This creates **nested AUX transactions within AUX transactions**, which could lead to lock recursion issues (the AUX mutex), or at minimum add very long delays (potentially tens of milliseconds per retry iteration).

The comment references "Spec DP2.1 Section 2.11.7.1.5.8" but the cover letter references "Section 2.3.4" — these should be consistent and correct.

**Performance:** On a disconnected sink (the common timeout case per the existing comment at line 410), this will add significant delay to every AUX probe by attempting to wake a non-existent device on every timeout retry.

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