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/edid: parse panel type from DisplayID 2.x Display Parameters
Date: Mon, 25 May 2026 22:19:21 +1000
Message-ID: <review-patch2-20260520021432.1301326-3-chen-yu.chen@amd.com>
In-Reply-To: <20260520021432.1301326-3-chen-yu.chen@amd.com>
References: <20260520021432.1301326-1-chen-yu.chen@amd.com> <20260520021432.1301326-3-chen-yu.chen@amd.com>
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Patch Review

**Purpose:** Adds parsing of the Display Device Technology field from the D=
isplay Parameters Data Block (tag 0x21).

**Struct layout:** `displayid_block` base is 3 bytes (tag + rev + num_bytes=
). The struct `displayid_display_params_block` places `payload[27]` then `d=
evice_tech_byte` at offset 30 from the block start (3 + 27 =3D 30 =3D 0x1E)=
, which matches the spec reference. The `DISPLAYID_DISPLAY_PARAMS_MIN_LEN` =
calculation (29 bytes of payload) and the `num_bytes` check are correct.

**Parsing logic:** Using `FIELD_GET(DISPLAYID_DISPLAY_PARAMS_DEVICE_TECH, .=
..)` to extract bits [6:4] is correct and clean.

**UAPI concern (significant):**

```c
+#define DRM_MODE_PANEL_TYPE_LCD		2
```

This adds a new UAPI constant, but `drm_panel_type_enum_list` in `drivers/g=
pu/drm/drm_connector.c` currently only contains:

```c
static const struct drm_prop_enum_list drm_panel_type_enum_list[] =3D {
	{ DRM_MODE_PANEL_TYPE_UNKNOWN, "unknown" },
	{ DRM_MODE_PANEL_TYPE_OLED, "OLED" },
};
```

Without adding `{ DRM_MODE_PANEL_TYPE_LCD, "LCD" }` to this list, the panel=
 type property will never report LCD to userspace. If LCD is meant to be in=
ternal-only, it shouldn't be in `include/uapi/drm/drm_mode.h`. If it's mean=
t to be exposed, the enum list needs updating.

**`did_panel_type` field:** Adding a `u8` to `drm_display_info` is fine. Th=
e reset in `drm_reset_display_info()` is correct.

**Version gate:** The check `displayid_version(&iter) =3D=3D DISPLAY_ID_STR=
UCTURE_VER_20` before parsing the block is correct =E2=80=94 tag 0x21 is on=
ly valid in DisplayID v2.x.

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