#!/usr/bin/env python3
"""
Patch 1: gfx_v10_0.c — Disable GFXOFF for Cyan Skillfish (IP 10.1.3)

Layer 1 of the v3 three-layer protection. Prevents the GPU from entering the
GFXOFF power-saving state, from which it cannot reliably wake. When the GPU is
unresponsive, any MMIO register read hangs the CPU indefinitely on the BC-250's
internal PCIe fabric (no completion timeout).

Usage:
    python3 patch1_gfxoff.py /path/to/drivers/gpu/drm/amd/amdgpu
"""
import sys
import os

if len(sys.argv) < 2:
    print("Usage: python3 patch1_gfxoff.py <amdgpu_source_dir>")
    print("  e.g.: python3 patch1_gfxoff.py ~/kernel-build/linux-6.19.6/drivers/gpu/drm/amd/amdgpu")
    sys.exit(1)

AMDGPU = sys.argv[1]
filepath = os.path.join(AMDGPU, "gfx_v10_0.c")

if not os.path.isfile(filepath):
    print(f"ERROR: File not found: {filepath}")
    sys.exit(1)

with open(filepath, 'r') as f:
    content = f.read()

if 'BC-250' in content:
    print("Already patched, skipping.")
    sys.exit(0)

# Find gfx_v10_0_check_gfxoff_flag function
func_start = content.find('static void gfx_v10_0_check_gfxoff_flag')
if func_start == -1:
    print("ERROR: gfx_v10_0_check_gfxoff_flag not found")
    sys.exit(1)

# Find the 'default:' case in the switch inside this function
func_region_end = func_start + 2000
default_pos = content.find('\tdefault:', func_start, func_region_end)
if default_pos == -1:
    default_pos = content.find('default:', func_start, func_region_end)
    if default_pos == -1:
        print("ERROR: default case not found in gfx_v10_0_check_gfxoff_flag")
        print("Region:", content[func_start:func_start+500])
        sys.exit(1)

# Insert our case BEFORE the default case
new_case = (
    '\t/* ===== BC-250 v3 PATCH START ===== */\n'
    '\tcase IP_VERSION(10, 1, 3):\n'
    '\t\t/*\n'
    '\t\t * BC-250 / Cyan Skillfish (gfx1013): GFXOFF causes the GPU to\n'
    '\t\t * enter a power-saving state from which it cannot reliably wake.\n'
    '\t\t * Unconditionally disable GFXOFF to prevent GPU hangs.\n'
    '\t\t */\n'
    '\t\tadev->pm.pp_feature &= ~PP_GFXOFF_MASK;\n'
    '\t\tdev_info(adev->dev,\n'
    '\t\t\t "BC-250: GFXOFF disabled to prevent GPU power-state hangs\\n");\n'
    '\t\tbreak;\n'
    '\t/* ===== BC-250 v3 PATCH END ===== */\n'
)

content = content[:default_pos] + new_case + content[default_pos:]

with open(filepath, 'w') as f:
    f.write(content)

print("Patch 1 applied: gfx_v10_0.c — GFXOFF disable for Cyan Skillfish (IP 10.1.3)")