Converging some additional requirements for FRL enablement

Hi there; I have been working on more broad community implementation for generic FRL in software (mainly for validation and providing a community/HDMI consortia free implementation(fully legal in NZ). I did a quick look this morning between your patch set and my working tree. This is AI based analysis but might be helpful. I've attached a repomix.xml to this issue of one of the revisions of where I had got to. Hopefully this is somewhat helpful.

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# AMD FRL Enablement: Directory & File Structure

This document outlines the complete file structure for the **Hybrid Integration Model**. It maps the "Brain" (Repomix protocol helpers) and the "Hands" (Mkopec hardware sequences) into the standard Linux kernel directory hierarchy, specifically tailored for the target `mkopec` branch state.

## 1. Directory Tree Visualization

```text
drivers/gpu/drm/
├── Kconfig                          [Modified: Upstream Reorder + DRM_HDMI_FRL]
├── Makefile                         [Modified: Links new FRL objects]
├── drm_edid.c                       [Modified: Exports HF-VSDB parsing helpers]
│
├── drm_hdmi_frl_tables.c            [New: Repomix - FRL Pattern/Rate Tables]
├── drm_hdmi_frl_helper.c            [New: Repomix - Bandwidth Math & Validation]
├── drm_hdmi_frl_software.c          [New: Repomix - Software FEC Dispatcher]
├── drm_hdmi_frl_fec_avx2.c          [New: Repomix - Software FEC (Guarded)]
├── drm_hdmi_frl_fec_neon.c          [New: Repomix - Software FEC (Guarded)]
│
├── drm_hdmi_emp.c                   [New: Repomix - Extended Metadata Packets]
├── drm_hdmi_qms_helper.c            [New: Repomix - Quick Media Switching]
├── drm_hdmi_audio_helper.c          [New: Repomix - 3D Audio Packets]
├── drm_hdmi_earc_helper.c           [New: Repomix - eARC / LIP Sync]
├── drm_hdmi_dynamic_hdr.c           [New: Repomix - Dynamic HDR Metadata]
├── drm_hdmi_hdcp_helper.c           [New: Repomix - HDCP 2.3 Protocol]
│
└── amd/
    └── display/
        └── dc/
            ├── core/
            │   ├── dc_link.c        [Modified: Hybrid - State Machine Glue]
            │   └── dc_resource.c    [Modified: Hybrid - Bandwidth Logic]
            │
            ├── dcn30/
            │   └── dcn30_hwseq.c    [Modified: Mkopec - Clock Gating/Routing]
            │
            └── dcn31/
                ├── dcn31_hpo_dp_link_encoder.c  [Modified: Mkopec - The "FRL Hack"]
                └── dcn31_hpo_dp_link_encoder.h  [Modified: Mkopec - Definitions]

include/drm/                         [New Section: Based on include diff]
├── drm_edid.h                       [Modified: Exposes HF-VSDB structs]
├── drm_connector.h                  [Modified: Adds FRL capability structs]
├── drm_hdmi_frl_helper.h            [New: Repomix - Prototypes]
├── drm_hdmi_audio_helper.h          [New: Repomix - Prototypes]
├── drm_hdmi_earc_helper.h           [New: Repomix - Prototypes]
├── drm_hdmi_emp.h                   [New: Repomix - Prototypes]
└── drm_hdmi_hdcp_helper.h           [New: Repomix - Prototypes]
```

## 2. Generic DRM Subsystem (`drivers/gpu/drm/`)

*These files provide the protocol "Brain" and are derived primarily from the Repomix codebase.*

### **A. Core Logic & Tables**

#### `drm_hdmi_frl_tables.c`
* **Origin:** Repomix
* **Purpose:** The "Truth Source" for HDMI 2.1 specs.
* **Key Content:**
    * `const u32 frl_rate_bandwidths[]`: {0, 9, 18, 24, 32, 40, 48} (Gbps).
    * `const u8 frl_pattern_ltp1[]` through `ltp8`: Binary definitions of Link Training Patterns.
    * **Export:** Must use `EXPORT_SYMBOL_GPL(drm_hdmi_frl_bandwidths);` etc.

#### `drm_hdmi_frl_helper.c`
* **Origin:** Repomix (Math Subset)
* **Purpose:** Calculates requirements without touching hardware.
* **Key Functions:**
    * `int drm_hdmi_frl_bandwidth_required(const struct drm_display_mode *mode, int bpc, int format);`
    * `bool drm_hdmi_frl_check_validity(const struct drm_connector *connector, int rate);`

#### `drm_hdmi_frl_software.c`
* **Origin:** Repomix
* **Purpose:** The software FEC dispatcher.
* **Key Content:**
    * **Integration:** Used primarily for validation/testing or non-DCN targets. Should be guarded by `CONFIG_DRM_HDMI_FRL_SOFTWARE`.
    * **Function:** `drm_hdmi_frl_fec_encode_software(void *buf, size_t len)` -> dispatches to AVX2/Neon implementation.

### **B. Advanced Protocol Features**

#### `drm_hdmi_emp.c`
* **Origin:** Repomix
* **Purpose:** Handles **Extended Metadata Packets (EMP)**.
* **Context:** Used for Dynamic HDR, VRR, and 3D Audio.
* **Integration:** `drm_hdmi_emp_pack(struct hdmi_emp_data *data, u8 *buffer, size_t size);`

#### `drm_hdmi_qms_helper.c`
* **Origin:** Repomix
* **Purpose:** **Quick Media Switching (QMS)** support.
* **Integration:** Requires deep hooks into AMD's `dc_stream` timing logic to ensure the vertical blanking interval is adjusted seamlessly.

#### `drm_hdmi_dynamic_hdr.c`
* **Origin:** Repomix
* **Purpose:** Handles Dynamic HDR (Dolby Vision / HDR10+) metadata.

### **C. Audio & Security**

#### `drm_hdmi_audio_helper.c`
* **Origin:** Repomix
* **Purpose:** Enables High-Bitrate Audio (HBR) and 3D Audio over FRL.
* **Key Content:** Implements "Audio Clock Regeneration" (ACR) packet logic (`N` and `CTS` values) which differs for FRL compared to TMDS.

#### `drm_hdmi_earc_helper.c`
* **Origin:** Repomix
* **Purpose:** **Enhanced Audio Return Channel (eARC)**.
* **Key Content:** State machine for eARC discovery and Common Mode negotiation.

#### `drm_hdmi_hdcp_helper.c`
* **Origin:** Repomix
* **Purpose:** HDCP 2.3 Protocol State Machine.
* **Usage:** Use only for protocol state tracking. AMD `psp` driver handles the crypto.

### **D. Core Infrastructure Modifications (Zero Loss)**

#### `drm_edid.c`
* **Origin:** Upstream (Modified)
* **Purpose:** Parses the raw binary EDID from the Sink.
* **The Gap:** Mainline 6.18 parses the HDMI Forum VSDB (HF-VSDB) but may not expose all FRL-specific flags (e.g., *DSC-with-FRL* constraints or *VRR-min/max* specifically for FRL modes).
* **Modification:**
    * Locate `drm_edid_parse_hf_vsdb`.
    * **Do not delete** existing logic.
    * **Add:** Parsing for `SCDC_Present` and `RR_Capable` (Read Request) if missing.
    * **Add:** Extraction of `Max_FRL_Rate` into `connector->display_info.hdmi.frl_rate`.

## 3. Build System Integration (The Merge)

### **A. Kconfig Integration Strategy**
*Context: `drivers_gpu_drm.diff` moves driver sources to the top.*

**File:** `drivers/gpu/drm/Kconfig`

```kconfig
# ... existing generic DRM configs (DRM_SCHED, etc) ...

# [INSERTION POINT START]
# Place this BEFORE the reordered source list in your diff
config DRM_HDMI_FRL
    bool "HDMI 2.1 FRL Support"
    depends on DRM
    select DRM_HDMI_HELPER
    help
      Enable support for Fixed Rate Link (FRL) signaling.
      Required for HDMI 2.1 bandwidths > 18Gbps.

config DRM_HDMI_FRL_SOFTWARE
    bool "HDMI 2.1 Software FEC (Debug)"
    depends on DRM_HDMI_FRL
    help
      Enables software-based Forward Error Correction.
      WARNING: CPU intensive. Use only for validation or virtual drivers.
# [INSERTION POINT END]

# The reordered list from your diff follows here:
source "drivers/gpu/drm/sysfb/Kconfig"
source "drivers/gpu/drm/arm/Kconfig"
source "drivers/gpu/drm/radeon/Kconfig"
source "drivers/gpu/drm/amd/amdgpu/Kconfig"
```

### **B. Makefile Integration**
**File:** `drivers/gpu/drm/Makefile`

```makefile
# ... existing obj-y ...
# Append these lines:

# Repomix Protocol Stack
obj-$(CONFIG_DRM_HDMI_FRL) += drm_hdmi_frl_tables.o \
                              drm_hdmi_frl_helper.o \
                              drm_hdmi_emp.o \
                              drm_hdmi_dynamic_hdr.o \
                              drm_hdmi_audio_helper.o \
                              drm_hdmi_earc_helper.o \
                              drm_hdmi_qms_helper.o \
                              drm_hdmi_hdcp_helper.o

# Software FEC (Guarded)
obj-$(CONFIG_DRM_HDMI_FRL_SOFTWARE) += drm_hdmi_frl_software.o \
                                       drm_hdmi_frl_fec_avx2.o \
                                       drm_hdmi_frl_fec_neon.o
```

## 4. AMD Display Core Integration (`amd/display/`)

### **A. Logic Integration (`dc/core/`)**

#### `dc_link.c`: The Decision Matrix
You must modify `dc_link_decide_link_settings` (or equivalent) to check for FRL conditions.

```c
/* PSEUDO-CODE for dc_link.c integration */

#include <drm/drm_hdmi_frl_helper.h>

bool dc_link_decide_frl_enable(struct dc_link *link, struct dc_stream_state *stream)
{
    // 1. Calculate Required Bandwidth using Repomix helper
    //    Convert DC stream format to DRM format constants first
    int bw_needed = drm_hdmi_frl_bandwidth_required(
        &stream->timing, 
        stream->bpc, 
        stream->pixel_encoding
    );

    // 2. Check if TMDS is sufficient (<= 18Gbps / 600MHz)
    if (bw_needed <= 18000)
        return false; // Stay on TMDS

    // 3. Check if Sink supports FRL (parsed from EDID)
    if (!link->hdmi_frl_caps.supported)
        return false; // Cap at HDMI 2.0

    // 4. Check if we exceed max FRL rate
    if (bw_needed > 48000)
        return false; // Mode not supported

    // 5. Success - Enable FRL
    return true;
}
```

#### `dc_resource.c`: Unlocking Bandwidth
* **Action:** Find `resource_validate_bandwidth`.
* **Change:** Remove the check `if (pixel_clk > 600000) return FAIL;` for HDMI signals.
* **Replace with:** `if (pixel_clk > 600000 && !frl_enabled) return FAIL;`

### **B. Hardware Abstraction (`dc/dcn31/`)**

#### `dcn31_hpo_dp_link_encoder.c`: The "FRL Hack"
* **Purpose:** The HPO (High Performance Output) block is the only PHY fast enough for 48Gbps. On AMD, it is nominally for DisplayPort 2.0.
* **Mechanism:** usage of `mkopec`'s register values forces the HPO block to construct HDMI packets instead of DP micro-packets.
* **Critical Modification:** In `hpo_dp_link_encoder_enable_dp_output`, add a check:
    ```c
    if (signal == SIGNAL_TYPE_HDMI_TYPE_A) {
        // configure HPO for FRL specifically
        // (Insert mkopec specific register writes here)
    }
    ```

## 5. DRM Header Subsystem (`include/drm/`)

*New files required to support the Repomix source code.*

#### `drm_edid.h` (Modified)
* **Purpose:** Expose the HF-VSDB offsets and parsing capabilities.
* **Zero Loss Change:** Add `DRM_EDID_HDMI_FORUM_VSDB` constant if missing. Add `struct drm_hdmi_forum_vsdb` definition if private in `.c` file.

#### `drm_connector.h` (Modified)
* **Action:** Check `struct drm_connector` or `struct drm_display_info`.
* **Add:**
    ```c
    struct drm_hdmi_frl_caps {
        bool supported;
        u8 max_lanes; // 3 or 4
        u8 max_rate_per_lane; // 3, 6, 8, 10, 12 Gbps
        bool scdc_present;
        bool qms_vrr_supported;
    };
    // Add 'struct drm_hdmi_frl_caps frl' to drm_display_info
    ```

#### `drm_hdmi_frl_helper.h`
* **Structs:**
    * `enum hdmi_frl_rate { HDMI_FRL_RATE_NONE, HDMI_FRL_RATE_3L_3G, ... };`
    * `struct hdmi_frl_config { enum hdmi_frl_rate rate; bool fec_enabled; };`
* **Prototypes:**
    * `drm_hdmi_frl_bandwidth_required(...)`

#### `drm_hdmi_emp.h`
* **Structs:**
    * `struct hdmi_emp_data { u8 type; u8 length; u8 *payload; };` (Extended Metadata Packet definition).

[repomix-output.xml](https://github.com/user-attachments/files/25374387/repomix-output.xml)

Converging some additional requirements for FRL enablement #1

Description

AMD FRL Enablement: Directory & File Structure

1. Directory Tree Visualization

2. Generic DRM Subsystem (drivers/gpu/drm/)

A. Core Logic & Tables

drm_hdmi_frl_tables.c

drm_hdmi_frl_helper.c

drm_hdmi_frl_software.c

B. Advanced Protocol Features

drm_hdmi_emp.c

drm_hdmi_qms_helper.c

drm_hdmi_dynamic_hdr.c

C. Audio & Security

drm_hdmi_audio_helper.c

drm_hdmi_earc_helper.c

drm_hdmi_hdcp_helper.c

D. Core Infrastructure Modifications (Zero Loss)

drm_edid.c

3. Build System Integration (The Merge)

A. Kconfig Integration Strategy

B. Makefile Integration

4. AMD Display Core Integration (amd/display/)

A. Logic Integration (dc/core/)

dc_link.c: The Decision Matrix

dc_resource.c: Unlocking Bandwidth

B. Hardware Abstraction (dc/dcn31/)

dcn31_hpo_dp_link_encoder.c: The "FRL Hack"

5. DRM Header Subsystem (include/drm/)

drm_edid.h (Modified)

drm_connector.h (Modified)

drm_hdmi_frl_helper.h

drm_hdmi_emp.h

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2. Generic DRM Subsystem (`drivers/gpu/drm/`)

`drm_hdmi_frl_tables.c`

`drm_hdmi_frl_helper.c`

`drm_hdmi_frl_software.c`

`drm_hdmi_emp.c`

`drm_hdmi_qms_helper.c`

`drm_hdmi_dynamic_hdr.c`

`drm_hdmi_audio_helper.c`

`drm_hdmi_earc_helper.c`

`drm_hdmi_hdcp_helper.c`

`drm_edid.c`

4. AMD Display Core Integration (`amd/display/`)

A. Logic Integration (`dc/core/`)

`dc_link.c`: The Decision Matrix

`dc_resource.c`: Unlocking Bandwidth

B. Hardware Abstraction (`dc/dcn31/`)

`dcn31_hpo_dp_link_encoder.c`: The "FRL Hack"

5. DRM Header Subsystem (`include/drm/`)

`drm_edid.h` (Modified)

`drm_connector.h` (Modified)

`drm_hdmi_frl_helper.h`

`drm_hdmi_emp.h`