Claude review: drm/bridge: dw-hdmi-qp: use drm_hdmi_acr_get_n_cts() helper for audio N/CTS

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

Patch Review

**Correctness: Good**

The conversion is straightforward and correct. The call site at line 255:

```c
drm_hdmi_acr_get_n_cts(tmds_char_rate, sample_rate, &n, &cts);
```

replaces the two separate calls:

```c
n = dw_hdmi_qp_find_n(hdmi, tmds_char_rate, sample_rate);
cts = dw_hdmi_qp_find_cts(hdmi, tmds_char_rate, sample_rate);
```

The helper always returns a non-zero CTS (it has a `DIV_ROUND_CLOSEST_ULL` fallback at line 421-422 of `drm_hdmi_helper.c` for any entry where `cts == 0`), which means `dw_hdmi_qp_set_cts_n()` will now always take the `AUDPKT_ACR_CTS_OVR_EN` path (line 125-127) — i.e., software-override CTS rather than hardware auto-measurement. This is the behavioral fix: the old code returned `cts = 0` for out-of-table TMDS rates, disabling CTS override and relying on the controller's broken auto-measurement.

**Type compatibility: Good**

The function parameter `tmds_char_rate` is declared `unsigned long long` in `dw_hdmi_qp_set_sample_rate()`, matching the helper's signature (`unsigned long long tmds_char_rate`). The struct field `hdmi->tmds_char_rate` is `unsigned long` (line 88) which is implicitly widened at the call site (line 291) — no truncation risk.

**Include: Already present**

`<drm/display/drm_hdmi_helper.h>` is already included at line 21, so no additional include is needed.

**Behavioral subtlety worth noting (not a bug):**

The removed open-coded N table had optimized N values for many non-CEA TMDS rates (28.32–162 MHz). For those rates, the helper falls back to `N = 128 * Fs / 1000`, which is the HDMI 1.4b recommended default — functionally correct but may produce slightly different jitter characteristics than the removed optimized values. The commit message acknowledges this explicitly and states no regression was observed. This is acceptable.

**Commit message quality: Excellent**

The commit message is thorough: it explains the root cause (CTS=0 at out-of-table rates), the fix mechanism, testing matrix with four TMDS rates, and the behavioral trade-off for non-CEA N values. The `Assisted-by: Claude:claude-opus-4-7` trailer follows `Documentation/process/coding-assistants.rst`. All tags (Reported-by, Closes, Suggested-by, Tested-by, Signed-off-by) are present and well-formed.

**No issues found. Patch is ready to merge.**

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Generated by Claude Code Patch Reviewer