Waveshare DSI display configuration guide for Volumio OS
KNOWN ISSUE: Intermittent dark display on cold boot (Raspberry Pi 4)
Waveshare 7.9" and 11.9" DSI displays may fail to initialize on cold boot while diagnostics report success (DSI connected, backlight on, xrandr shows output). Confirmed on Pi 4 revisions 1.2, 1.4, and 1.5 running kernel 6.x.
Cause: The Waveshare ws_touchscreen driver attempts I2C communication with the panel controller (address 0x45) without initialization delay or retry logic. On cold boot, the panel controller may not be ready, resulting in:
ws_touchscreen 10-0045: I2C write failed: -5
Behavior pattern:
- Short power cycle (under 10 seconds): More likely to succeed
- Long power down (overnight): More likely to fail
- Multiple reboots: May eventually succeed
This is a Waveshare driver defect, not a configuration problem. The configurations in this guide are correct. Contact Waveshare support and reference this error if you experience this issue.
Supported hardware
Raspberry Pi models
- Raspberry Pi 4B+ - Tested with all scenarios
- Raspberry Pi 5 - Tested with all scenarios
Waveshare DSI displays
- 11.9 inch DSI LCD - Native resolution 320x1480 (portrait)
- 7.9 inch DSI LCD - Native resolution 400x1280 (portrait)
Operating system
- Volumio OS (Debian Bookworm-based)
Display-specific parameters reference
All configurations require display-specific parameters. Use this table to determine correct values for your display.
Parameter table by display size
| Parameter | 11.9 inch display | 7.9 inch display |
|---|---|---|
| Native resolution | 320x1480 (portrait) | 400x1280 (portrait) |
| Rotated resolution | 1480x320 (landscape) | 1280x400 (landscape) |
| dtoverlay line | dtoverlay=vc4-kms-dsi-waveshare-panel,11_9_inch,rotation=270 |
dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch,rotation=270 |
| video= parameter | video=DSI-1:320x1480@60,rotate=270 |
video=DSI-1:400x1280e,rotate=270 |
| Expected fbset output | mode "1480x320" |
mode "1280x400" |
Important notes:
- Both displays use
rotation=270in dtoverlay for landscape orientation - 7.9 inch display requires “e” flag in video= parameter:
400x1280e - 11.9 inch display does NOT use “e” flag:
320x1480@60
Complete example configurations
This section provides complete, ready-to-use configuration files for common setups. Choose the example matching your hardware and copy the entire configuration.
Example 1: Raspberry Pi 4B+ with 11.9 inch display (Scenario 1)
Complete /boot/userconfig.txt:
# Add your custom config.txt options to this file, which will be preserved during updates
[pi4]
dtoverlay=vc4-kms-v3d-pi4
dtoverlay=vc4-kms-dsi-waveshare-panel,11_9_inch,rotation=270
hdmi_force_hotplug=0
disable_overscan=1
dtparam=audio=off
[all]
Add to end of /boot/cmdline.txt:
video=DSI-1:320x1480@60,rotate=270
Expected fbset output:
mode "1480x320"
Example 2: Raspberry Pi 5 with 11.9 inch display (Scenario 1)
Complete /boot/userconfig.txt:
# Add your custom config.txt options to this file, which will be preserved during updates
dtoverlay=vc4-kms-dsi-waveshare-panel,11_9_inch,rotation=270
hdmi_force_hotplug=0
hdmi_drive=2
disable_overscan=1
Add to end of /boot/cmdline.txt:
video=DSI-1:320x1480@60,rotate=270
Expected fbset output:
mode "1480x320"
Example 3: Raspberry Pi 4B+ with 7.9 inch display (Scenario 1)
Complete /boot/userconfig.txt:
# Add your custom config.txt options to this file, which will be preserved during updates
[pi4]
dtoverlay=vc4-kms-v3d-pi4
dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch,rotation=270
hdmi_force_hotplug=0
disable_overscan=1
dtparam=audio=off
[all]
Add to end of /boot/cmdline.txt:
video=DSI-1:400x1280e,rotate=270
Note: The “e” flag is required for 7.9 inch display.
Expected fbset output:
mode "1280x400"
Example 4: Raspberry Pi 5 with 7.9 inch display (Scenario 1)
Complete /boot/userconfig.txt:
# Add your custom config.txt options to this file, which will be preserved during updates
dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch,rotation=270
hdmi_force_hotplug=0
hdmi_drive=2
disable_overscan=1
Add to end of /boot/cmdline.txt:
video=DSI-1:400x1280e,rotate=270
Note: The “e” flag is required for 7.9 inch display.
Expected fbset output:
mode "1280x400"
Example 5: Raspberry Pi 4B+ with 11.9 inch + HDMI port 0 audio (Scenario 3)
Complete /boot/userconfig.txt:
# Add your custom config.txt options to this file, which will be preserved during updates
[pi4]
dtoverlay=vc4-kms-v3d-pi4
dtoverlay=vc4-kms-dsi-waveshare-panel,11_9_inch,rotation=270
hdmi_force_hotplug:0=1
hdmi_drive:0=2
hdmi_ignore_edid:0=0xa5000080
disable_overscan=1
[all]
Add to end of /boot/cmdline.txt:
video=DSI-1:320x1480@60,rotate=270 video=HDMI-A-1:d
Expected result: Display on DSI, audio from HDMI port 0
Example 6: Raspberry Pi 5 with 7.9 inch + both HDMI ports audio (Scenario 5)
Complete /boot/userconfig.txt:
# Add your custom config.txt options to this file, which will be preserved during updates
dtoverlay=vc4-kms-dsi-waveshare-panel,7_9_inch,rotation=270
hdmi_force_hotplug:0=1
hdmi_force_hotplug:1=1
hdmi_drive:0=2
hdmi_drive:1=2
hdmi_ignore_edid:0=0xa5000080
hdmi_ignore_edid:1=0xa5000080
disable_overscan=1
Add to end of /boot/cmdline.txt:
video=DSI-1:400x1280e,rotate=270 video=HDMI-A-1:d video=HDMI-A-2:d
Expected result: Display on DSI, audio from both HDMI ports (Volumio uses one)
Physical orientation (270-degree rotation)
Raspberry Pi 4B+ and Pi 5 mounting (when viewing from screen side):
- Bottom edge: USB-C power port, HDMI ports
- Left edge: USB ports, Ethernet/LAN port
- Top edge: GPIO header
- Right edge: SD card slot (micro SD on Pi 4B+, full size SD on Pi 5)
Note: When mounting the Pi from behind (looking at the back of the display), left and right edges are reversed from this description.
Display orientation with 270-degree rotation:
- Display top edge: Aligned with GPIO header (Pi top edge)
- Display bottom edge: Aligned with USB-C/HDMI ports (Pi bottom edge)
Configuration scenarios overview
| Scenario | Audio output | HDMI port 0 | HDMI port 1 | Use case |
|---|---|---|---|---|
| 1 | None/Disabled | Disabled | Disabled | Minimal setup, no audio |
| 2 | I2S DAC | Disabled | Disabled | High-quality audio via DAC |
| 3 | HDMI audio | Audio only | Disabled | Soundbar/AVR on HDMI 0 |
| 4 | HDMI audio | Disabled | Audio only | Soundbar/AVR on HDMI 1 |
| 5 | HDMI audio | Audio only | Audio only | Dual audio output capability |
Common base configuration
Raspberry Pi 4B+
All scenarios share this base configuration in /boot/userconfig.txt:
[pi4]
dtoverlay=vc4-kms-v3d-pi4
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
disable_overscan=1
Add scenario-specific parameters below this base.
Raspberry Pi 5
All scenarios use this simplified configuration in /boot/userconfig.txt:
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug=0
hdmi_drive=2
disable_overscan=1
Key differences for Pi 5:
- No section markers ([pi4], [all]) needed
- No vc4-kms-v3d overlay (handled automatically by volumioconfig.txt)
- Simplified HDMI configuration
Add scenario-specific parameters below this base.
cmdline.txt configuration
For all scenarios on both Pi 4B+ and Pi 5:
Add the display-specific video= parameter from the table to the END of /boot/cmdline.txt:
<INSERT DISPLAY-SPECIFIC video= PARAMETER FROM TABLE>
Space-separate from previous parameters.
Example for 11.9 inch display:
... use_kmsg=no video=DSI-1:320x1480@60,rotate=270
Example for 7.9 inch display:
... use_kmsg=no video=DSI-1:400x1280e,rotate=270
Scenario 1: DSI only (no audio)
Purpose
Minimal configuration for display only, all audio outputs disabled.
Configuration
Raspberry Pi 4B+
/boot/userconfig.txt:
[pi4]
dtoverlay=vc4-kms-v3d-pi4
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug=0
disable_overscan=1
dtparam=audio=off
[all]
Raspberry Pi 5
/boot/userconfig.txt:
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug=0
hdmi_drive=2
disable_overscan=1
Both Pi 4B+ and Pi 5
/boot/cmdline.txt:
- Add to the END of the existing single line:
<INSERT DISPLAY-SPECIFIC video= PARAMETER FROM TABLE> - Space-separate from previous parameters
Expected results
fbsetshows display-specific resolution (see parameter table)- No HDMI interference
- Plymouth displays correctly on DSI with landscape rotation
- Console properly rotated to landscape
- No audio outputs active
Scenario 2: DSI + I2S DAC
Purpose
High-quality audio through external I2S DAC while maintaining DSI display.
Configuration
Raspberry Pi 4B+
/boot/userconfig.txt:
[pi4]
dtoverlay=vc4-kms-v3d-pi4
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug=0
disable_overscan=1
dtparam=audio=off
[all]
Raspberry Pi 5
/boot/userconfig.txt:
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug=0
hdmi_drive=2
disable_overscan=1
Both Pi 4B+ and Pi 5
/boot/cmdline.txt:
- Add to the END of the existing single line:
<INSERT DISPLAY-SPECIFIC video= PARAMETER FROM TABLE> - Space-separate from previous parameters
DAC Configuration via Volumio UI:
Do NOT add DAC overlays to userconfig.txt. Configure your I2S DAC through Volumio’s web interface:
- Open Volumio web UI (http://volumio.local)
- Navigate to: Settings → Playback Options
- Under Output Device, select your I2S DAC from the dropdown
- Click Save
- Volumio will automatically add the correct DAC overlay to
/boot/config.txt - Reboot when prompted
Important: Volumio manages DAC configuration in /boot/config.txt (system file). User modifications should only go in /boot/userconfig.txt. The two files work together - config.txt is managed by Volumio, userconfig.txt is for user customizations like display settings.
Expected results
fbsetshows display-specific resolution (see parameter table)- I2S DAC active for audio output (configured via Volumio UI)
- Plymouth displays correctly on DSI with landscape rotation
- Console properly rotated to landscape
- HDMI audio disabled
Scenario 3: DSI + HDMI port 0 audio
Purpose
Extract audio from HDMI port 0 (closer to USB-C power) while disabling video output.
Configuration
Raspberry Pi 4B+
/boot/userconfig.txt:
[pi4]
dtoverlay=vc4-kms-v3d-pi4
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug:0=1
hdmi_drive:0=2
hdmi_ignore_edid:0=0xa5000080
disable_overscan=1
[all]
Raspberry Pi 5
/boot/userconfig.txt:
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug:0=1
hdmi_drive:0=2
hdmi_ignore_edid:0=0xa5000080
disable_overscan=1
Both Pi 4B+ and Pi 5
/boot/cmdline.txt:
- Add to the END of the existing single line:
<INSERT DISPLAY-SPECIFIC video= PARAMETER FROM TABLE> video=HDMI-A-1:d - Space-separate from previous parameters
Example for 11.9 inch display:
... use_kmsg=no video=DSI-1:320x1480@60,rotate=270 video=HDMI-A-1:d
Expected results
fbsetshows display-specific resolution (see parameter table)- HDMI-A-1 video disabled but audio active
- Plymouth displays correctly on DSI with landscape rotation
- Console properly rotated to landscape
- HDMI audio available to soundbar/AVR connected to port 0
Scenario 4: DSI + HDMI port 1 audio
Purpose
Extract audio from HDMI port 1 (farther from USB-C power) while disabling video output.
Configuration
Raspberry Pi 4B+
/boot/userconfig.txt:
[pi4]
dtoverlay=vc4-kms-v3d-pi4
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug:1=1
hdmi_drive:1=2
hdmi_ignore_edid:1=0xa5000080
disable_overscan=1
[all]
Raspberry Pi 5
/boot/userconfig.txt:
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug:1=1
hdmi_drive:1=2
hdmi_ignore_edid:1=0xa5000080
disable_overscan=1
Both Pi 4B+ and Pi 5
/boot/cmdline.txt:
- Add to the END of the existing single line:
<INSERT DISPLAY-SPECIFIC video= PARAMETER FROM TABLE> video=HDMI-A-2:d - Space-separate from previous parameters
Example for 11.9 inch display:
... use_kmsg=no video=DSI-1:320x1480@60,rotate=270 video=HDMI-A-2:d
Expected results
fbsetshows display-specific resolution (see parameter table)- HDMI-A-2 video disabled but audio active
- Plymouth displays correctly on DSI with landscape rotation
- Console properly rotated to landscape
- HDMI audio available to soundbar/AVR connected to port 1
Scenario 5: DSI + both HDMI ports audio
Purpose
Extract audio from both HDMI ports simultaneously while disabling video output.
Configuration
Raspberry Pi 4B+
/boot/userconfig.txt:
[pi4]
dtoverlay=vc4-kms-v3d-pi4
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug:0=1
hdmi_force_hotplug:1=1
hdmi_drive:0=2
hdmi_drive:1=2
hdmi_ignore_edid:0=0xa5000080
hdmi_ignore_edid:1=0xa5000080
disable_overscan=1
[all]
Raspberry Pi 5
/boot/userconfig.txt:
<INSERT DISPLAY-SPECIFIC dtoverlay LINE FROM TABLE>
hdmi_force_hotplug:0=1
hdmi_force_hotplug:1=1
hdmi_drive:0=2
hdmi_drive:1=2
hdmi_ignore_edid:0=0xa5000080
hdmi_ignore_edid:1=0xa5000080
disable_overscan=1
Both Pi 4B+ and Pi 5
/boot/cmdline.txt:
- Add to the END of the existing single line:
<INSERT DISPLAY-SPECIFIC video= PARAMETER FROM TABLE> video=HDMI-A-1:d video=HDMI-A-2:d - Space-separate from previous parameters
Example for 11.9 inch display:
... use_kmsg=no video=DSI-1:320x1480@60,rotate=270 video=HDMI-A-1:d video=HDMI-A-2:d
Expected results
fbsetshows display-specific resolution (see parameter table)- Both HDMI video outputs disabled but audio active on both ports
- Plymouth displays correctly on DSI with landscape rotation
- Console properly rotated to landscape
- HDMI audio available on both ports (Volumio will default to one)
Parameter reference
Display parameters
| Parameter | Function |
|---|---|
dtoverlay=vc4-kms-v3d-pi4 |
Enables VC4 KMS display driver for Pi 4 (Pi 4B+ only) |
dtoverlay=vc4-kms-dsi-waveshare-panel,<size>,rotation=270 |
Loads Waveshare DSI panel driver with 270-degree rotation |
video=DSI-1:<resolution>,rotate=270 |
Kernel-level framebuffer rotation for console |
disable_overscan=1 |
Prevents display area reduction (no black borders) |
HDMI audio parameters
| Parameter | Function |
|---|---|
hdmi_force_hotplug:N=1 |
Keeps HDMI port N active (0=first port, 1=second port) |
hdmi_drive:N=2 |
Forces HDMI audio mode (not DVI) on port N |
hdmi_ignore_edid:N=0xa5000080 |
Ignores display detection on port N (audio-only mode) |
video=HDMI-A-N:d |
Kernel-level disable of HDMI-A-N video output |
Audio parameters
| Parameter | Function |
|---|---|
dtparam=audio=off |
Disables onboard 3.5mm audio jack (Pi 4B+ only) |
dtoverlay=<dac-name> |
Loads specific I2S DAC driver overlay |
Verification commands
After rebooting with new configuration, verify setup with these commands:
Check framebuffer resolution
fbset
Expected output for 11.9 inch display:
mode "1480x320"
geometry 1480 320 1480 320 16
Expected output for 7.9 inch display:
mode "1280x400"
geometry 1280 400 1280 400 16
Check kernel command line
cat /proc/cmdline | grep video
Expected output for 11.9 inch (Scenario 3):
... video=DSI-1:320x1480@60,rotate=270 video=HDMI-A-1:d
Expected output for 7.9 inch (Scenario 3):
... video=DSI-1:400x1280e,rotate=270 video=HDMI-A-1:d
Check DSI display status
cat /sys/class/drm/card1-DSI-1/modes
cat /sys/class/drm/card1-DSI-1/status
Expected output for 11.9 inch:
320x1480
connected
Expected output for 7.9 inch:
400x1280
connected
Check HDMI configuration
vcgencmd get_config int | grep hdmi
Expected output (Scenario 3):
hdmi_drive:0=2
hdmi_force_hotplug:0=1
Check display devices
ls /sys/class/drm/
Expected output:
card0 card0-HDMI-A-1 card0-HDMI-A-2 card1 card1-DSI-1 ...
Troubleshooting
Issue: Framebuffer shows wrong resolution
Symptoms:
fbset
mode "320x480" # Wrong for 11.9 inch
mode "400x480" # Wrong for 7.9 inch
Causes:
- HDMI parameters injected by firmware before DSI configuration
- Conflicting video= parameters in cmdline.txt
- Missing video=DSI-1 rotation parameter
- Wrong display-specific parameters used
Solution:
- Verify
hdmi_force_hotplug=0in userconfig.txt (or proper port-specific settings) - Check
/proc/cmdlinefor unexpectedvideo=HDMIparameters - Ensure correct display-specific video= parameter from table is in cmdline.txt
- Verify video=DSI-1 parameter appears BEFORE any HDMI parameters
- Double-check you’re using parameters for the correct display size
Issue: Console in portrait mode despite rotation
Symptoms:
- Plymouth displays correctly rotated
- Console text appears in portrait orientation
- Login prompt sideways
Solution:
- Add display-specific
video=DSI-1:...parameter to cmdline.txt - This parameter rotates the framebuffer/console layer
- dtoverlay rotation alone only affects panel hardware, not console
- Verify you’re using the correct video= parameter for your display size
Issue: 7.9 inch display not working
Symptoms:
- Black screen or no output
- fbset shows wrong resolution
Solution:
- Verify video= parameter includes “e” flag:
video=DSI-1:400x1280e,rotate=270 - The “e” flag is required for 7.9 inch display
- 11.9 inch display does NOT use “e” flag
Issue: HDMI audio not working
Symptoms:
- No audio output from HDMI-connected device
- Volumio doesn’t list HDMI as audio output option
Solution:
- Verify
hdmi_drive:N=2is set (forces audio mode) - Check HDMI cable supports audio (not all do)
- Verify soundbar/AVR is set to correct HDMI input
- Check Volumio audio output settings in web interface
Issue: Plymouth not displaying during boot
Symptoms:
- Black screen during boot
- Boot messages appear but no Plymouth splash
Solution:
- Verify DSI display is detected:
cat /sys/class/drm/card1-DSI-1/status - Check Plymouth is enabled:
plymouth --ping - Review initramfs Plymouth script:
/scripts/init-premount/plymouth - Check kernel messages:
dmesg | grep -i plymouth
Issue: Display corruption or multiple segments
Symptoms:
- Screen shows multiple copies of content
- Distorted or rotated incorrectly
Solution:
- Ensure dtoverlay rotation matches video= rotation (both 270 degrees)
- Never use different rotation values in dtoverlay vs video= parameter
- Check for duplicate rotation specifications
- Verify using correct display-specific parameters
Notes and best practices
Important warnings
- Never edit
/boot/config.txtdirectly - Always use/boot/userconfig.txtfor custom settings - cmdline.txt is a single line - All parameters must be on one line, space-separated
- Rotation values must match - dtoverlay rotation and video= rotation must be identical
- DSI parameter goes first - Place video=DSI-1 before any HDMI parameters in cmdline.txt
- Use correct display parameters - 11.9 inch and 7.9 inch require different parameters
- 7.9 inch needs “e” flag - video= parameter must include “e”:
400x1280e - Firmware interference - hdmi_force_hotplug triggers automatic HDMI detection
- Configure DACs via Volumio UI - Never manually add DAC overlays to userconfig.txt; use Settings → Playback Options instead
File preservation
These files are preserved during Volumio updates:
/boot/userconfig.txt- User configuration for display and custom hardware (safe to edit)/boot/cmdline.txt- Kernel parameters (safe to edit)
These files are managed by Volumio:
/boot/config.txt- System configuration managed by Volumio (do not edit directly)/boot/volumioconfig.txt- Volumio base config (do not edit)
Important distinction:
/boot/config.txt- Volumio writes system settings here (DAC configuration, base hardware settings)/boot/userconfig.txt- User adds custom settings here (display configuration, additional hardware)- Both files are processed together at boot
- Settings in userconfig.txt supplement (not replace) config.txt
- Never manually add DAC overlays to userconfig.txt - use Volumio UI instead
Configuration testing workflow
- Identify your display size (11.9 inch or 7.9 inch)
- Reference the parameter table for display-specific values
- Make changes to configuration files using correct parameters
- Verify syntax (no typos, proper spacing)
- Reboot system
- Run verification commands
- Check Plymouth during boot
- Verify console rotation
- Test audio output if configured
- Document working configuration
Rotation angles reference
| Rotation | Native portrait | Landscape result | Display top edge aligns with |
|---|---|---|---|
| 0 | Native portrait | Portrait mode | N/A - portrait mode |
| 90 | Native portrait | Landscape | SD card slot (Pi right edge) |
| 180 | Native portrait | Portrait upside down | N/A - portrait upside down |
| 270 | Native portrait | Landscape | GPIO header (Pi top edge) |
This guide uses 270-degree rotation for landscape display with GPIO header at top.
Why both dtoverlay and video= rotation?
- dtoverlay rotation: Rotates panel at hardware/driver level
- video= rotation: Rotates framebuffer/console layer at kernel level
- Both required: Panel needs hardware rotation, console needs framebuffer rotation
- Values must match: Using different rotation values causes display corruption
Document information
- Version: 2.3
- Date: 2025-12-14
- Hardware: Raspberry Pi 4B+ and Raspberry Pi 5
- Displays: Waveshare 11.9" DSI LCD (320x1480), Waveshare 7.9" DSI LCD (400x1280)
- OS: Volumio (Debian Bookworm-based)
- Author: Technical documentation for Volumio DSI display configuration
- Testing status: All scenarios tested on Pi 4B+ and Pi 5 with 11.9" display; 7.9" parameters verified
- Update notes:
- Version 2.0 - Restructured for equal treatment of both display sizes
- Version 2.1 - Corrected Scenario 2: DAC configuration via Volumio UI, not userconfig.txt
- Version 2.2 - Added complete example configurations for all Pi/display combinations
- Version 2.3 - Added known issue notice for Waveshare I2C timing bug; removed duplicate section
References
- Waveshare 11.9" DSI LCD Wiki: https://www.waveshare.com/wiki/11.9inch_DSI_LCD
- Waveshare 7.9" DSI LCD Wiki: https://www.waveshare.com/wiki/7.9inch_DSI_LCD
- Raspberry Pi configuration documentation: https://www.raspberrypi.com/documentation/computers/config_txt.html
- Volumio documentation: https://volumio.com/en/documentation/
- Linux kernel video mode documentation: modedb default video mode support — The Linux Kernel documentation
.