From mboxrd@z Thu Jan  1 00:00:00 1970
From: Claude Code Review Bot <claude-review@example.com>
To: dri-devel-reviews@example.com
Subject: Claude review: drm: rcar-du: encoder: convert to of_drm_find_and_get_bridge()
Date: Sun, 12 Apr 2026 11:12:50 +1000
Message-ID: <review-patch2-20260409-drm-bridge-alloc-getput-drm_of_find_bridge-4-v5-2-d7381c07788a@bootlin.com>
In-Reply-To: <20260409-drm-bridge-alloc-getput-drm_of_find_bridge-4-v5-2-d7381c07788a@bootlin.com>
References: <20260409-drm-bridge-alloc-getput-drm_of_find_bridge-4-v5-0-d7381c07788a@bootlin.com> <20260409-drm-bridge-alloc-getput-drm_of_find_bridge-4-v5-2-d7381c07788a@bootlin.com>
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Patch Review

**Status: Good to merge.**

This is the more complex patch because `rcar_du_encoder_init()` stores bridge pointers in long-lived `rcdu->lvds[]` and `rcdu->dsi[]` arrays, requiring explicit cleanup.

**Refcounting analysis for stored references:**

```c
rcdu->lvds[output - RCAR_DU_OUTPUT_LVDS0] =
    drm_bridge_get(bridge);
```

This neatly takes a new reference and assigns it in one expression. After function return, `__free` puts the local reference, and `rcdu->lvds[]` retains its own independent reference. Same pattern for `dsi[]`.

**Cleanup correctness:**

The new `rcar_du_encoder_cleanup()`:
```c
for (i = 0; i < ARRAY_SIZE(rcdu->lvds); i++)
    drm_bridge_put(rcdu->lvds[i]);
for (i = 0; i < ARRAY_SIZE(rcdu->dsi); i++)
    drm_bridge_put(rcdu->dsi[i]);
```

This is safe for NULL entries (the `DEFINE_FREE` pattern at `drm_bridge.h:1297` checks for NULL, and `drm_bridge_put()` itself should handle NULL). It's called from `rcar_du_modeset_cleanup()` which is registered via `drmm_add_action()` early in `rcar_du_modeset_init()` (line 857) -- before `rcar_du_encoders_init()` is called (line 955). This ensures cleanup runs even if encoder init fails partway through.

**Early return paths after lvds/dsi storage:**

The `-ENOLINK` returns at lines 98 and 103 happen after `rcdu->lvds[]` may have been populated with an extra reference. This is safe because:
1. `__free` puts the local reference
2. The stored reference in `rcdu->lvds[]` will be put by `rcar_du_encoder_cleanup()` via the already-registered `drmm_add_action`
3. The caller (`rcar_du_encoders_init`) handles `-ENOLINK` with `continue`, and other error paths also eventually tear down via drmm

**One observation** (not a blocker): `drm_bridge_put()` is called directly rather than going through `if (ptr)` guards in `rcar_du_encoder_cleanup()`. This relies on `drm_bridge_put()` handling NULL gracefully. Checking the `DEFINE_FREE` at `drm_bridge.h:1297` shows it does check `if (_T)`, and looking at standard kernel conventions, `drm_bridge_put(NULL)` should be a no-op. This is fine.

No issues.

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