269 lines
6.3 KiB
Markdown
269 lines
6.3 KiB
Markdown
# KDE Plasma Installation and Revert Guide for reTerminal DM4
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## Device Information
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- **Model**: Raspberry Pi Compute Module 4 (CM4)
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- **CPU**: Cortex-A72 (4 cores)
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- **RAM**: 8GB
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- **Current Desktop**: LXDE with Openbox
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- **Display**: 10-inch, 1280x800
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## Pre-Installation State
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### Current Desktop Packages
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- libobrender32v5
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- libobt2v5:arm64
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- lxsession
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- lxsession-data
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- lxsession-logout
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- openbox
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- pcmanfm
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### Current Session Manager
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- Default: `/usr/bin/startx-rpd` (priority 90)
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- Available: `/usr/bin/lxsession` (priority 49)
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- Available: `/usr/bin/openbox-session` (priority 40)
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- Current mode: auto (points to startx-rpd)
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### Available Desktop Sessions
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- lightdm-xsession.desktop
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- openbox.desktop
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- rpd-x.desktop
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### Installation Date
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- Date: 2026-01-09
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---
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## Installation Steps
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### Step 1: Update System
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```bash
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sudo apt-get update
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sudo apt-get upgrade -y
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```
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### Step 2: Install KDE Plasma
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```bash
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# Install KDE Plasma desktop (lightweight version)
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sudo apt-get install -y kde-plasma-desktop
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# Install on-screen keyboard for touchscreen
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sudo apt-get install -y maliit-keyboard
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# Install additional KDE utilities
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sudo apt-get install -y kde-standard
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```
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### Step 3: Configure Default Desktop
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**Option A: Switch at Login (Recommended - Safest)**
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1. Log out of current session
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2. At login screen, click on the session/desktop selector (usually in top-right corner)
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3. Select "Plasma (X11)" or "plasmax11"
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4. Log in
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**Option B: Set as Default**
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```bash
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# Set KDE as default desktop session
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sudo update-alternatives --config x-session-manager
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# Select: /usr/bin/startplasma-x11 (priority 40)
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```
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**Note**: KDE Plasma X11 session is available at `/usr/share/xsessions/plasmax11.desktop`
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### Step 4: Configure Touchscreen Settings
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After logging into KDE:
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1. **Enable On-Screen Keyboard:**
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- System Settings > Input Devices > Virtual Keyboard
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- Enable "Show on-screen keyboard when needed"
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2. **Adjust Touch Settings:**
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- System Settings > Input Devices > Touchpad/Touchscreen
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- Adjust touch sensitivity
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- Enable tap-to-click
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3. **UI Scaling for Touch:**
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- System Settings > Display and Monitor
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- Set scale to 125% or 150% for better touch targets
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4. **Disable Heavy Effects (for better performance):**
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- System Settings > Workspace Behavior > Desktop Effects
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- Disable resource-intensive effects
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- Keep basic animations enabled
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### Step 5: Reboot
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```bash
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sudo reboot
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```
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---
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## Post-Installation Verification
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After reboot, verify KDE is working:
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```bash
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echo $XDG_CURRENT_DESKTOP
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# Should show: KDE or plasma
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ps aux | grep -i plasma
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# Should show KDE processes running
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```
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---
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## Cloud-Init (Automated Install)
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For EMMC provisioning you can install KDE, set it as the default session, and enable touch options automatically using cloud-init. Use the example that includes KDE and touch:
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- **File:** `emmc-provisioning/cloud-init/user-data-kiosk-username-ssh.example`
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It installs `kde-plasma-desktop`, `maliit-keyboard`, and `xinput-calibrator`; sets LightDM default session to Plasma (X11); writes KDE config for touch-friendly scaling and touch-point feedback; and autostarts the on-screen keyboard. Chromium kiosk and SSH are configured in the same example. Replace the password hash and use it as your cloud-init `user-data` when building the image.
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---
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## Reverting to LXDE
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### Method 1: Switch at Login Screen (Easiest)
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1. Log out of current session
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2. At the login screen, click on the session/desktop selector (usually top-right)
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3. Select "Openbox" or "RPD-X" session
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4. Log in
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### Method 1b: Use Revert Script
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A revert script is provided: `revert-to-lxde.sh`
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```bash
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# Copy script to device and run
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./revert-to-lxde.sh
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```
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### Method 2: Change Default Session
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```bash
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# Set LXDE as default
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sudo update-alternatives --config x-session-manager
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# Select LXDE option (usually /usr/bin/startlxde or similar)
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```
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### Method 3: Remove KDE (Complete Revert)
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If you want to completely remove KDE:
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```bash
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# Remove KDE packages
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sudo apt-get remove --purge kde-plasma-desktop kde-standard
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sudo apt-get autoremove -y
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sudo apt-get autoclean
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# Restore LXDE as default
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sudo update-alternatives --config x-session-manager
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# Select LXDE
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# Reboot
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sudo reboot
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```
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### Method 4: Reinstall LXDE (if removed)
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If LXDE was accidentally removed:
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```bash
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sudo apt-get update
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sudo apt-get install --reinstall lxde
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sudo update-alternatives --config x-session-manager
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```
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---
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## Troubleshooting
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### KDE Won't Start
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```bash
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# Check if KDE is installed
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dpkg -l | grep kde-plasma
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# Check available sessions
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ls /usr/share/xsessions/
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# Try starting KDE manually
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startplasma-wayland
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# or
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startplasma-x11
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```
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### Performance Issues
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- Disable desktop effects in System Settings
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- Reduce animation duration
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- Use X11 instead of Wayland (if Wayland is causing issues)
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### Touchscreen Not Working
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```bash
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# Check touchscreen device
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xinput list
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# Calibrate touchscreen
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sudo apt-get install xinput-calibrator
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xinput_calibrator
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```
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### Chromium Autostart Issues
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Your existing Chromium autostart configuration should work with KDE.
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If it doesn't, check:
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```bash
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cat ~/.config/autostart/chromium-kiosk.desktop
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```
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---
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## Performance Notes
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- **Expected RAM Usage**: 400-800MB for KDE Plasma
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- **Expected CPU Usage**: Low to moderate (Cortex-A72 handles it well)
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- **Boot Time**: Slightly longer than LXDE (~10-15 seconds more)
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---
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## Files Modified/Created
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- `/usr/share/xsessions/` - Desktop session files
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- `~/.config/plasma-org.kde.plasma.desktop-appletsrc` - KDE panel configuration
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- `~/.config/kwinrc` - Window manager settings
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- `~/.config/plasmarc` - Plasma settings
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---
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## Backup Before Installation
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To create a backup of current desktop settings:
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```bash
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# Backup current desktop configuration
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mkdir -p ~/desktop-backup
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cp -r ~/.config/lx* ~/desktop-backup/ 2>/dev/null
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cp -r ~/.config/openbox ~/desktop-backup/ 2>/dev/null
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```
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---
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## Rollback Checklist
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If you need to revert:
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- [ ] Switch session at login screen (easiest)
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- [ ] Change default session via update-alternatives
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- [ ] Remove KDE packages if needed
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- [ ] Verify LXDE is working
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- [ ] Check Chromium autostart still works
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- [ ] Verify touchscreen calibration
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---
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## Support
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If you encounter issues:
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1. Check system logs: `journalctl -xe`
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2. Check X/Wayland logs: `~/.xsession-errors`
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3. Verify packages: `dpkg -l | grep kde`
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4. Check available sessions: `ls /usr/share/xsessions/`
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