amd-bc250-docs/docs/hardware/display.md

Display Connectivity

Guide to connecting displays to the BC-250 and troubleshooting display issues.

Display Output Overview

Available Connectors

• DisplayPort: 1x full-size DisplayPort 1.4
• HDMI: None (requires adapter)
• Resolution Support: Up to 4K @120Hz
• HDR Support: Yes (HDR10)

!!!info "DisplayPort Only" The BC-250 only has DisplayPort output. For HDMI displays, you'll need a DP to HDMI adapter.

DisplayPort Direct Connection

Recommended Setup

DisplayPort Cable:

• Version: DisplayPort 1.4 certified
• Length: 1-2m (longer cables can cause issues)
• Quality: Use certified cables (VESA DP certified)

Resolution Support:

• 1920x1080 (1080p) @ 144Hz+
• 2560x1440 (1440p) @ 144Hz+
• 3840x2160 (4K) @ 120Hz

!!!success "Native DisplayPort Recommended" If your monitor has DisplayPort, use it directly. This avoids adapter compatibility issues.

Audio Over DisplayPort

Status: Works for most users

Confirmed Working Monitors:

• MSI 27CQ6F (direct DP connection)
• Various Dell/HP monitors
• Most modern DisplayPort monitors

Configuration:

# Check audio devices
aplay -l

# Select HDMI/DisplayPort audio in system settings
# Usually appears as "HDMI/DisplayPort" or "AMD/ATI"

Troubleshooting Audio:

• Some monitors don't pass through audio
• Check monitor specs for audio support
• Verify speakers are enabled on monitor
• Test with headphones/external speakers first

DP to HDMI Adapters

Adapter Types

Passive Adapters (Recommended):

• Audio: Usually works reliably
• Cost: Inexpensive ($5-10)
• Use Case: Most users, TV connections
• Note: DP 1.2 max (1440p @60Hz, some support 1440p @165Hz)

Active Adapters (Use with Caution):

• Audio: Often broken or unreliable
• Cost: More expensive ($15-30)
• Use Case: Only if you need 4K @120Hz+
• Issues: Audio compatibility problems common

Known Issues with Adapters

!!!warning "Audio Problems with Adapters" Many DP to HDMI adapters break audio functionality. This is a known limitation.

Common Symptoms:

• Display works, no audio
• Audio works intermittently
• Audio dropouts/clicking

Workarounds:

1. Use USB audio adapter/DAC
2. Use 3.5mm audio cable (no audio output on BC-250)
3. Use Bluetooth audio
4. Try different adapter brand

Tested Adapter Compatibility

Adapter Type	Display Works	Audio Works	Notes
Generic Passive	Usually	Sometimes	Hit or miss
Cable Matters Active	Yes	No	4K works, no audio
Club3D Active	Yes	Sometimes	Sporadic audio issues
StarTech Active	Yes	No	Reliable display, no audio

!!!info "Audio Adapter Limitation" If you need audio, consider a USB audio adapter ($10-20) as a reliable solution.

Common Display Problems

No Display on Boot

Symptoms:

• Monitor shows "No Signal"
• System appears to be running (fans spin)
• Power LED on board is lit

Causes:

1. No GPU drivers installed
2. Incorrect kernel parameters
3. Bad cable/adapter
4. Monitor incompatibility

Solutions:

Step 1: Boot with nomodeset

# At GRUB, press 'e' to edit boot entry
# Find line starting with 'linux' or 'linuxefi'
# Add 'nomodeset' to end of line
# Press Ctrl+X to boot

Step 2: Verify cable/adapter

• Try different DisplayPort cable
• Try display on another system
• Remove adapter if using one

Step 3: Check BIOS settings

• Verify display output is enabled
• Try resetting BIOS to defaults

See Display Troubleshooting Guide for detailed steps.

Black Screen After Login

Symptoms:

• GRUB menu displays
• Login screen displays
• Black screen after logging in

Cause: Desktop environment issue, usually Wayland

Solutions:

Option 1: Switch to X11

1. At login screen, select user
2. Click gear icon (bottom right)
3. Select "GNOME on Xorg" or "Plasma (X11)"
4. Log in

Option 2: Disable Wayland

# Edit GDM config
sudo nano /etc/gdm/custom.conf

# Uncomment this line:
WaylandEnable=false

# Save and reboot

Display Works But Low Resolution

Symptoms:

• Display detected but stuck at 1024x768 or 1920x1080
• Higher resolutions not available
• Refresh rate limited to 60Hz

Causes:

• GPU drivers not loaded
• Using software rendering (llvmpipe)
• Bad cable limiting bandwidth

Check Current Driver:

glxinfo | grep "OpenGL renderer"
# Should show: AMD Radeon Graphics (RADV GFX1013)
# If shows: llvmpipe - drivers not working

Solutions:

1. Install Mesa 25.1+ drivers
2. Remove nomodeset from GRUB
3. Use certified DisplayPort cable
4. Update monitor firmware

See Mesa Installation Guide

Flickering or Artifacts

Symptoms:

• Screen flickers occasionally
• Visual artifacts (lines, blocks)
• Colors incorrect

Causes:

• Bad cable
• Interference
• Overclocking too high
• Insufficient cooling

Solutions:

1. Replace DisplayPort cable
2. Reduce GPU overclock
3. Check GPU temperature
4. Try different monitor input

HDMI 2.1 / 4K @120Hz Issues

Limitation: DP to HDMI adapters often limited to HDMI 2.0

HDMI 2.0 Limits:

• 4K @ 60Hz
• No 4K @ 120Hz
• Limited HDR

HDMI 2.1 Requirement:

• Requires active DP 1.4 to HDMI 2.1 adapter
• Still may have compatibility issues

!!!tip "Use Native DisplayPort" For high refresh rate 4K gaming, use a native DisplayPort monitor instead of adapter.

Multiple Display Support

Limitations

Hardware:

• Only 1 physical DisplayPort output
• No multi-monitor support from single board

Options for Multiple Displays:

Option 1: USB DisplayLink Adapter

• Add USB to HDMI/DisplayPort adapter
• Works for desktop use (plug in after boot for best results)
• Not suitable for gaming — high latency due to CPU-based compression, BC-250's CPU is the bottleneck
• Does not work in Steam Deck game mode

Option 2: DisplayPort MST Hub

• Split single DP into multiple displays
• Maximum 2 screens via MST on BC-250
• Shares bandwidth between displays
• Works for productivity
• Limited resolution per display

Option 3: Multiple BC-250 Boards

• Use separate board per monitor
• Impractical for most users

Display Configuration

Setting Resolution and Refresh Rate

KDE Plasma:

1. System Settings → Display and Monitor
2. Select your display
3. Choose resolution and refresh rate
4. Apply

GNOME:

1. Settings → Displays
2. Select resolution from dropdown
3. Click Apply

Command Line (xrandr):

# List available modes
xrandr

# Set mode
xrandr --output DisplayPort-0 --mode 1920x1080 --rate 144

Custom Resolutions

Some monitors may require custom modelines:

# Generate modeline
cvt 2560 1440 144

# Add to xrandr
xrandr --newmode "2560x1440_144.00" ...
xrandr --addmode DisplayPort-0 "2560x1440_144.00"

HDR Configuration

HDR support in Linux is improving but still experimental:

Check HDR Support:

# KDE Plasma 6+: HDR toggle in display settings
# GNOME: Limited HDR support

Notes:

• HDR support varies by desktop environment
• KDE Plasma 6+ has best HDR support
• May require Wayland session
• Game-specific HDR may not work

Audio Solutions

Since audio over HDMI adapters is unreliable, here are alternative solutions:

Option 1: USB Audio Adapter

Recommended Adapters:

• Creative Sound Blaster Play! 4
• Sabrent USB Audio Adapter
• FiiO K3 DAC (audiophile option)

Setup:

1. Plug USB audio adapter into BC-250 USB port
2. Connect speakers/headphones to adapter
3. Select USB audio device in system settings

Option 2: Bluetooth Audio

Requirements:

• USB Bluetooth adapter
• Bluetooth speakers/headphones

Setup:

# Install Bluetooth tools
sudo dnf install bluez bluez-tools  # Fedora
sudo pacman -S bluez bluez-utils    # Arch

# Enable Bluetooth
sudo systemctl enable --now bluetooth

# Pair device (use GUI or bluetoothctl)

Latency Warning: Bluetooth adds ~100-200ms latency, noticeable in gaming

Option 3: Monitor with Displayport + Speakers

If your monitor has DisplayPort input AND built-in speakers:

• Audio over DisplayPort usually works
• Check monitor supports audio input
• Enable speakers in monitor settings

Troubleshooting Checklist

Before Asking for Help

1. Verify hardware:

   • Cable is securely connected both ends
   • Monitor works with another device
   • Power LED on monitor is lit

2. Check software:

   # GPU detected?
   lspci | grep VGA
   
   # Driver loaded?
   lsmod | grep amdgpu
   
   # Mesa version?
   glxinfo | grep "OpenGL version"
   

3. Test with nomodeset:

   • If display works with nomodeset, driver issue
   • If no display with nomodeset, hardware issue

4. Try different cable/adapter:

   • Cables can fail
   • Adapters have compatibility issues

5. Check logs:

   # Check for errors
   dmesg | grep -i amdgpu
   journalctl -b | grep -i drm
   

Display Recommendations by Use Case

Gaming @ 1080p 144Hz

• Display: Any 1080p 144Hz+ DisplayPort monitor
• Cable: DP 1.4 certified cable
• Expected: Works flawlessly

Gaming @ 1440p 144Hz

• Display: 1440p 144Hz+ DisplayPort monitor
• Cable: DP 1.4 certified, <2m length
• Expected: Works well

4K @ 60Hz

• Display: 4K 60Hz monitor with DisplayPort OR HDMI
• Cable: DP 1.4 cable OR active DP-to-HDMI adapter
• Audio: Use USB audio if adapter needed

4K @ 120Hz

• Display: 4K 120Hz DisplayPort monitor
• Cable: DP 1.4 certified cable
• Note: May need to manually set 120Hz in settings

TV Connection (Living Room Gaming)

• Display: 4K TV with HDMI 2.0+
• Adapter: Active DP to HDMI 2.0 adapter
• Audio: Use TV speakers (if adapter supports audio) OR Bluetooth/USB audio
• Note: Test adapter audio before permanent setup

See Also

• Troubleshooting Display Issues (Detailed)
• Hardware Specifications
• BIOS Configuration
• Mesa Driver Installation