Add aggressive HDMI power control to prevent display shutdown

Enhanced Raspberry Pi HDMI power management:

Boot Configuration (/boot/config.txt):
- hdmi_blanking=0 - Disable HDMI blanking
- hdmi_force_hotplug=1 - Force HDMI mode always on
- hdmi_ignore_cec_init=1 - Disable HDMI CEC interference
- hdmi_ignore_edid=0xa5000080 - Disable HDMI sleep mode

New systemd services:
- hdmi-poweron.service - Runs tvservice -p every 30 seconds
- screen-keepalive.service - Aggressive display keep-alive script

Display keep-alive script (.display-keepalive.sh):
- tvservice -p - Force HDMI to stay powered
- xset commands - Keep X11 screensaver off
- xdotool - Mouse movement for activity detection
- xrandr - Disable monitor power profile saving
- 30-second loop for continuous power signaling

Enhanced app-level control (main.py):
- DISPLAY=:0 environment variable for X11 commands
- tvservice integration in signal_screen_activity()
- xrandr power profile management
- More aggressive DPMS disabling

This addresses HDMI being powered down at multiple levels:
1. Firmware level (boot config)
2. System level (systemd services)
3. X11 level (xset, xdotool, xrandr)
4. App level (continuous signaling)

HDMI output should now remain powered throughout playback.

.player_heartbeat

@@ -1 +1 @@
-1768670593.7002711
+1768672780.5973904

install.sh

@@ -151,7 +151,33 @@ setup_raspberry_pi_power_management() {
         else
             echo "hdmi_blanking=0" | sudo tee -a /boot/config.txt > /dev/null
         fi
-        echo "✓ HDMI screen blanking disabled"
+        
+        # Disable HDMI CEC (can interfere with power management)
+        if grep -q "hdmi_ignore_cec_init" /boot/config.txt; then
+            sudo sed -i 's/^hdmi_ignore_cec_init=.*/hdmi_ignore_cec_init=1/' /boot/config.txt
+        else
+            echo "hdmi_ignore_cec_init=1" | sudo tee -a /boot/config.txt > /dev/null
+        fi
+        
+        # Force HDMI mode to always be on
+        if grep -q "hdmi_force_hotplug" /boot/config.txt; then
+            sudo sed -i 's/^hdmi_force_hotplug=.*/hdmi_force_hotplug=1/' /boot/config.txt
+        else
+            echo "hdmi_force_hotplug=1" | sudo tee -a /boot/config.txt > /dev/null
+        fi
+        
+        # Disable HDMI sleep mode
+        if grep -q "hdmi_ignore_edid" /boot/config.txt; then
+            sudo sed -i 's/^hdmi_ignore_edid=.*/hdmi_ignore_edid=0xa5000080/' /boot/config.txt
+        else
+            echo "hdmi_ignore_edid=0xa5000080" | sudo tee -a /boot/config.txt > /dev/null
+        fi
+        
+        echo "✓ HDMI configuration locked in /boot/config.txt"
+        echo "  - HDMI blanking disabled"
+        echo "  - HDMI CEC disabled"
+        echo "  - HDMI hotplug forced"
+        echo "  - HDMI sleep mode disabled"
     fi
     
     # Disable screensaver and screen blanking in X11
@@ -295,7 +321,71 @@ EOF
     chmod +x "$KEEPALIVE_SCRIPT"
     echo "✓ Screen keep-alive service created"
     
-    # Create systemd service to run keep-alive service
+    # Create systemd service to keep HDMI powered on
+    echo "Creating HDMI power control service..."
+    sudo tee /etc/systemd/system/hdmi-poweron.service > /dev/null << 'EOF'
+[Unit]
+Description=Keep HDMI Display Powered On
+After=multi-user.target display-manager.service
+
+[Service]
+Type=simple
+ExecStart=/bin/bash -c 'while true; do /usr/bin/tvservice -p 2>/dev/null; sleep 30; done'
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+EOF
+    
+    sudo systemctl daemon-reload
+    sudo systemctl enable hdmi-poweron.service
+    sudo systemctl start hdmi-poweron.service
+    echo "✓ HDMI power control service enabled"
+    
+    # Create aggressive display keep-alive script
+    echo "Creating aggressive display keep-alive script..."
+    DISPLAY_KEEPALIVE="$SCRIPT_DIR/.display-keepalive.sh"
+    cat > "$DISPLAY_KEEPALIVE" << 'EOF'
+#!/bin/bash
+# Aggressive display keep-alive for Raspberry Pi
+# Prevents HDMI from powering down
+
+DISPLAY_TIMEOUT=30
+
+while true; do
+    # Keep HDMI powered on (tvservice command)
+    if command -v tvservice &> /dev/null; then
+        /usr/bin/tvservice -p 2>/dev/null
+    fi
+    
+    # Disable screensaver
+    if command -v xset &> /dev/null; then
+        DISPLAY=:0 xset s off 2>/dev/null
+        DISPLAY=:0 xset -dpms 2>/dev/null
+        DISPLAY=:0 xset dpms force on 2>/dev/null
+        DISPLAY=:0 xset s reset 2>/dev/null
+    fi
+    
+    # Move mouse to trigger activity
+    if command -v xdotool &> /dev/null; then
+        DISPLAY=:0 xdotool mousemove_relative 1 1 2>/dev/null
+        DISPLAY=:0 xdotool mousemove_relative -1 -1 2>/dev/null
+    fi
+    
+    # Disable monitor power saving
+    if command -v xrandr &> /dev/null; then
+        DISPLAY=:0 xrandr --output HDMI-1 --power-profile performance 2>/dev/null || true
+    fi
+    
+    sleep $DISPLAY_TIMEOUT
+done
+EOF
+    
+    chmod +x "$DISPLAY_KEEPALIVE"
+    echo "✓ Display keep-alive script created"
+    
+    # Update systemd screen keep-alive service to use this script
     sudo tee /etc/systemd/system/screen-keepalive.service > /dev/null << EOF
 [Unit]
 Description=Keep Screen Awake During Signage Player
@@ -304,9 +394,12 @@ PartOf=graphical-session.target
 
 [Service]
 Type=simple
-ExecStart=/bin/bash -c 'while true; do xset s reset 2>/dev/null; sleep 30; done'
+User=$ACTUAL_USER
+ExecStart=/bin/bash $DISPLAY_KEEPALIVE
 Restart=always
 RestartSec=5
+Environment="DISPLAY=:0"
+Environment="XAUTHORITY=%h/.Xauthority"
 
 [Install]
 WantedBy=graphical-session.target
@@ -314,7 +407,7 @@ EOF
     
     sudo systemctl daemon-reload
     sudo systemctl enable screen-keepalive.service
-    echo "✓ Systemd screen keep-alive service enabled"
+    echo "✓ Aggressive screen keep-alive service enabled"
     
     echo ""
     echo "⚠️  Note: Some changes require a system reboot to take effect."

src/main.py

@@ -934,17 +934,28 @@ class SignagePlayer(Widget):
         1. xset s reset - Reset screensaver timeout
         2. xset dpms force on - Force display on
         3. xdotool - Move mouse to trigger activity
+        4. tvservice - Keep HDMI powered on (Raspberry Pi)
+        5. xrandr - Disable monitor power saving
         """
         try:
             # Method 1: Reset screensaver timer using xset
-            os.system('xset s reset 2>/dev/null')
+            os.system('DISPLAY=:0 xset s reset 2>/dev/null')
             
             # Method 2: Force display on
-            os.system('xset dpms force on 2>/dev/null')
+            os.system('DISPLAY=:0 xset dpms force on 2>/dev/null')
             
-            # Method 3: Move mouse slightly (subtle, user won't notice)
-            if os.system('xdotool mousemove_relative 1 1 2>/dev/null') == 0:
-                os.system('xdotool mousemove_relative -1 -1 2>/dev/null')
+            # Method 3: Disable DPMS
+            os.system('DISPLAY=:0 xset -dpms 2>/dev/null')
+            
+            # Method 4: Move mouse slightly (subtle, user won't notice)
+            if os.system('DISPLAY=:0 xdotool mousemove_relative 1 1 2>/dev/null') == 0:
+                os.system('DISPLAY=:0 xdotool mousemove_relative -1 -1 2>/dev/null')
+            
+            # Method 5: Keep HDMI powered on (Raspberry Pi specific)
+            os.system('/usr/bin/tvservice -p 2>/dev/null')
+            
+            # Method 6: Disable monitor power saving via xrandr
+            os.system('DISPLAY=:0 xrandr --output HDMI-1 --power-profile performance 2>/dev/null || true')
                 
             Logger.debug("SignagePlayer: Screen activity signal sent (display kept awake)")