2nd Monitor Not Waking Up Fix

#!/usr/bin/env python3
"""
dp3-wake-fix — Fix DP-3 external monitor after DPMS wake on Intel Arc / TC3 port.

Mechanism: Listens for X11 MIT-SCREEN-SAVER ScreenSaverNotify events. When the
display wakes from a DPMS blank (state=ScreenSaverOff), it waits briefly for the
i915 driver to attempt (and fail) link training, then forces xrandr to retrain the
link by reapplying the desired mode. No polling, no systemd suspend hooks.

Requires: python3-xlib  (sudo apt install python3-xlib)
Run as:   user mark, inside X session (DISPLAY=:0)
"""

import logging
import os
import subprocess
import sys
import time

# ---------------------------------------------------------------------------
# Configuration
# ---------------------------------------------------------------------------

DISPLAY_ENV   = ":0"
XAUTHORITY    = "/home/mark/.Xauthority"
DP3_OUTPUT    = "DP-3"
DP3_MODE      = "3840x2160"
DP3_RATE      = "100"
DP3_POS       = "0x0"
WAKE_DELAY    = 2.5   # seconds after wake before checking (let driver fail first)

# MIT-SCREEN-SAVER state constants (from Xss.h)
SS_OFF      = 0   # ScreenSaverOff  — display woke
SS_ON       = 1   # ScreenSaverOn   — display blanked
SS_NOTIFY_MASK = 1

# ---------------------------------------------------------------------------
# Logging
# ---------------------------------------------------------------------------

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s  %(levelname)-7s  %(message)s",
    handlers=[logging.StreamHandler(sys.stdout)],
)
log = logging.getLogger("dp3-wake-fix")

# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

def xenv() -> dict:
    env = os.environ.copy()
    env["DISPLAY"]    = DISPLAY_ENV
    env["XAUTHORITY"] = XAUTHORITY
    return env


def dp3_is_broken() -> bool:
    """
    Return True when DP-3 is connected but has no active resolution
    (the 'connected' line lacks a geometry like '3840x2160+0+0').
    """
    try:
        result = subprocess.run(
            ["xrandr", "--query"],
            capture_output=True, text=True, env=xenv(), timeout=5,
        )
        for line in result.stdout.splitlines():
            if line.startswith(f"{DP3_OUTPUT} connected"):
                broken = DP3_MODE not in line
                log.debug("xrandr line: %s  → broken=%s", line.strip(), broken)
                return broken
        log.debug("DP-3 not found in xrandr output (may be fully disconnected)")
        return False
    except Exception as exc:
        log.warning("xrandr query failed: %s", exc)
        return False


def fix_dp3() -> None:
    cmd = [
        "xrandr",
        "--output", DP3_OUTPUT,
        "--mode",   DP3_MODE,
        "--rate",   DP3_RATE,
        "--pos",    DP3_POS,
    ]
    log.info("Applying fix: %s", " ".join(cmd))
    try:
        result = subprocess.run(
            cmd, capture_output=True, text=True, env=xenv(), timeout=10,
        )
        if result.returncode == 0:
            log.info("Fix applied successfully.")
        else:
            log.error("xrandr failed (rc=%d): %s", result.returncode, result.stderr.strip())
    except Exception as exc:
        log.error("xrandr exception: %s", exc)


# ---------------------------------------------------------------------------
# Main event loop
# ---------------------------------------------------------------------------

def main() -> None:
    try:
        from Xlib import display as xdisplay
        from Xlib.ext import screensaver
    except ImportError:
        log.error("python3-xlib not installed.  Run:  sudo apt install python3-xlib")
        sys.exit(1)

    os.environ["DISPLAY"]    = DISPLAY_ENV
    os.environ["XAUTHORITY"] = XAUTHORITY

    try:
        d = xdisplay.Display(DISPLAY_ENV)
    except Exception as exc:
        log.error("Cannot connect to X display %s: %s", DISPLAY_ENV, exc)
        sys.exit(1)

    ext = d.query_extension("MIT-SCREEN-SAVER")
    if ext is None:
        log.error("MIT-SCREEN-SAVER extension not available on %s", DISPLAY_ENV)
        sys.exit(1)

    event_base = ext.first_event
    log.info("MIT-SCREEN-SAVER available (event base %d)", event_base)

    root = d.screen().root
    screensaver.select_input(root, SS_NOTIFY_MASK)
    d.flush()
    log.info("Subscribed to DPMS/ScreenSaver events on %s.  Waiting...", DISPLAY_ENV)

    while True:
        try:
            event = d.next_event()
        except KeyboardInterrupt:
            log.info("Interrupted — exiting.")
            break
        except Exception as exc:
            log.error("X event error: %s — retrying in 5s", exc)
            time.sleep(5)
            continue

        if event.type != event_base:
            continue

        state = getattr(event, "state", None)

        if state == SS_ON:
            log.info("Display blanked (DPMS on).")
        elif state == SS_OFF:
            log.info("Display woke (DPMS off) — waiting %.1fs for driver...", WAKE_DELAY)
            time.sleep(WAKE_DELAY)
            if dp3_is_broken():
                log.info("DP-3 in broken state — fixing.")
                fix_dp3()
            else:
                log.info("DP-3 looks fine — no action needed.")
        else:
            log.debug("ScreenSaverNotify state=%s (ignored)", state)


if __name__ == "__main__":
    main()