Known Software Issue — MIPI-DSI Display

⚠️ Affected hardware: Hailo-15 SOM mounted on the HB-IOT carrier board Interface: MIPI-DSI display output Status: Open — pending fix in a future Hailo-15 SDK release

Issue

On the Hailo-15 SOM paired with the HB-IOT carrier board, the MIPI-DSI display does not reliably come up on the first initialization attempt. This is a known software bug in the current Hailo-15 SDK DSI driver and is expected to be resolved in an upcoming SDK release from Hailo.

Workaround

Until an official fix is provided by Hailo, the display can be brought up reliably by retrying modetest several times before letting it run persistently. The steps below describe how to reproduce this workaround on the board.

1. Find the DSI connector ID

bash

modetest -M hailo-drm -c | awk '/DSI-1/ { print $1 }' | tr -d :

2. Run modetest in a retry loop

Start modetest, kill it quickly, retry, and on the final attempt let it stay alive. The following shell function implements this sequence:

bash

display_test() {
    ATTEMPTS=0
    MAX_ATTEMPTS=9
    CONNECTOR=$(modetest -M hailo-drm -c | awk '/DSI-1/ { print $1 }' | tr -d :)
    while true; do
        ATTEMPTS=$((ATTEMPTS + 1))
        if [ "$ATTEMPTS" -le "$MAX_ATTEMPTS" ]; then
            # Run modetest and kill after 0.2s - workaround for Hailo display bug
            modetest -M hailo-drm -s ${CONNECTOR}:1024x600-60@RG24 >/dev/null 2>&1 &
            MPID=$!
            sleep 0.2
            kill $MPID 2>/dev/null
            continue
        fi
        # On the last attempt - run and keep it alive
        ( modetest -M hailo-drm -s ${CONNECTOR}:1024x600-60@RG24 < /dev/tty0 > /dev/tty0 2>&1 ) &
        return 0
    done
}

3. Run the function

bash

display_test

Expected Result

After the final attempt, the display comes up showing modetest's built-in color-bar test pattern, confirming that the panel and driver path are functioning correctly.

✅ Success: If the color-bar test pattern appears on the MIPI-DSI panel, the workaround has been applied successfully and the display path is operational.

Notes

ℹ️ Note: This workaround is a temporary measure. The root cause lies in the Hailo-15 SDK MIPI-DSI drivers and should be addressed by Hailo in a future software release. SolidRun will update this guide once an official fix is available.