Redroid-rk3588 Kernel Patch Generation Script

中文版本

📋 Introduction

This script automatically generates the required Redroid kernel patches for Armbian RK3588. By comparing the official Armbian kernel with CNflysky's modified kernel, it extracts key differences that add support for the system-uncached-dma32 DMA heap device and generates a patch file that can be directly applied to the Armbian build process.

🎯 Why Do You Need This Script?

Background

• Redroid-rk3588 requires the kernel to provide the system-uncached-dma32 DMA heap device for GPU hardware acceleration
• This device was removed from the mainline Linux 6.1 kernel
• Armbian's default kernel (rk-6.1-rkr5.1 branch) does not include this device
• CNflysky added the necessary code in their forked kernel (rk-6.1-rkr4.1 branch)

Solution

Manually comparing two kernel branches and extracting differences is time-consuming and error-prone. This script automates the entire process, ensuring:

✅ Extract only necessary differences (DMA-BUF related code) ✅ Generate standard patch files conforming to Armbian patch format ✅ Repeatable execution for easy updates and maintenance

📦 Prerequisites

System Environment

• Operating System: Ubuntu 22.04 LTS or similar Debian-based distributions
• Memory: At least 8GB RAM
• Storage: At least 15GB free space
• Privileges: Recommended to run as root user (to avoid permission issues)

Required Tools

sudo apt update
sudo apt install -y git diffutils coreutils

Armbian Build Environment

The script needs to be used within a cloned Armbian build directory:

cd ~
git clone --depth=1 https://github.com/armbian/build

🚀 Usage

1. Get Script File

cd ~
wget https://github.com/HwlloChen/redroid-rk3588-armbian-kernel-patch/raw/refs/heads/main/generate_redroid_patch.sh

2. Chmod +x

chmod +x generate_redroid_patch.sh

3. Configure Parameters (Optional)

Configuration parameters at the top of the script can be modified as needed:

# Armbian build directory path
ARMBIAN_BUILD_DIR="$HOME/build"

# Armbian target kernel branch (adjust according to your build configuration)
TARGET_KERNEL_BRANCH="rk35xx-vendor-6.1"

# Base kernel branch (Armbian official)
ARMBIAN_KERNEL_BRANCH="rk-6.1-rkr5.1"

# Target kernel branch (CNflysky modified version)
CNFLYSKY_KERNEL_BRANCH="rk-6.1-rkr4.1"

Key Parameter Descriptions:

Parameter	Description	Default Value	When to Modify
ARMBIAN_BUILD_DIR	Armbian build directory path	$HOME/build	If build directory is in another location
TARGET_KERNEL_BRANCH	Your target kernel branch	rk35xx-vendor-6.1	Based on actual branch name shown by ./compile.sh
ARMBIAN_KERNEL_BRANCH	Armbian base branch	rk-6.1-rkr5.1	Usually no need to modify
CNFLYSKY_KERNEL_BRANCH	CNflysky kernel branch	rk-6.1-rkr4.1	Usually no need to modify

4. Run the Script

./generate_redroid_patch.sh

5. Verify Output

After successful execution, the patch file will be generated at:

~/build/userpatches/kernel/rk35xx-vendor-6.1/0002-dma-uncached-dma32.patch

Verify patch content:

cat ~/build/userpatches/kernel/rk35xx-vendor-6.1/0002-dma-uncached-dma32.patch

🔧 How It Works

Execution Flow

┌─────────────────────────────────────┐
│ 1. Clone Armbian Official Kernel   │
│    (Base) rk-6.1-rkr5.1             │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│ 2. Clone CNflysky Kernel (Target)   │
│    rk-6.1-rkr4.1                    │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│ 3. Compare Specified Path Diffs     │
│    - drivers/dma-buf/               │
│    - include/linux/dma-buf.h        │
│    - include/linux/dma-heap.h       │
│    - include/linux/android_kabi.h   │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│ 4. Generate Unified Format Patch    │
│    Using diff -Nurb                 │
└──────────────┬──────────────────────┘
               │
┌──────────────▼──────────────────────┐
│ 5. Output to Armbian userpatches/   │
│    Auto-applied to kernel builds    │
└─────────────────────────────────────┘

Key Technical Points

1. Precise Diff Extraction: Only compare DMA-BUF related files to avoid unnecessary changes
2. Unified Patch Format: Use diff -Nurb to generate GNU standard patches
3. Automatic Integration: Output to userpatches/kernel/ directory, automatically applied during Armbian compilation

❓ FAQ

Q1: Script fails with "Clone failed" error

Cause: Network issues or GitHub access restrictions

Solution:

# Configure Git proxy (if using proxy)
git config --global http.proxy http://127.0.0.1:7890

# Or use GitHub mirror
# Modify repository URLs in the script:
# https://github.com/armbian/linux-rockchip.git
# Change to
# https://mirror.ghproxy.com/https://github.com/armbian/linux-rockchip.git

Q2: Generated patch file is empty or very small

Cause: Kernel branch version mismatch, or file paths don't exist

Solution:

# Manually verify if branches exist in both repositories
git ls-remote https://github.com/armbian/linux-rockchip.git | grep rk-6.1-rkr5.1
git ls-remote https://github.com/CNflysky/linux-rockchip.git | grep rk-6.1-rkr4.1

Q3: Patch application fails during Armbian compilation

Cause: Target kernel branch name configured incorrectly

Solution:

1. Run ./compile.sh once and observe the actual kernel branch name used
2. Modify the TARGET_KERNEL_BRANCH parameter in the script
3. Regenerate the patch

Q4: Kernel compilation still fails after applying patch

Cause: Additional kernel configuration options may be required

Solution: Ensure the following are enabled in kernel configuration:

• CONFIG_ARM64_VA_BITS=39
• CONFIG_ANDROID_BINDERFS=y
• CONFIG_PSI=y
• CONFIG_DMABUF_HEAPS=y

📝 Patch File Description

Example of generated patch file format:

From: Redroid Contributor <[email protected]>
Subject: [PATCH 0002] dma-heap: Add system-uncached-dma32 and necessary files for Redroid GPU

---
diff -Nurb armbian-rkr5.1-base/drivers/dma-buf/dma-heap.c cnflysky-rkr4.1-target/drivers/dma-buf/dma-heap.c
--- armbian-rkr5.1-base/drivers/dma-buf/dma-heap.c	2024-01-01 00:00:00.000000000 +0000
+++ cnflysky-rkr4.1-target/drivers/dma-buf/dma-heap.c	2024-01-01 00:00:00.000000000 +0000
@@ -123,6 +123,9 @@
 	// ... patch content ...

🔗 Related Resources

• Armbian Build Documentation: https://docs.armbian.com/Developer-Guide_Build-Preparation/
• Redroid-rk3588 Project: https://github.com/CNflysky/redroid-rk3588
• CNflysky Kernel Repository: https://github.com/CNflysky/linux-rockchip
• Armbian Kernel Repository: https://github.com/armbian/linux-rockchip

📄 License

This script is licensed under MIT License.

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Tip: If you encounter issues during usage, please refer to the complete RK3588 Cloud Phone Setup Guide.