Why does the HDMI output show no signal on Genio even though the board boots?

The most common cause is the HDMI cable or monitor being connected after Weston has already started. Weston enumerates displays at startup — hot-plug after boot is supported but requires Weston to process the HPD (hot-plug detect) event. If the display stays black, try: (1) disconnect and reconnect the cable, (2) check that the HDMI cable is HDMI 2.0 rated if using 4K, (3) confirm the monitor is powered on before the board boots.

How do I force a specific HDMI resolution on Genio?

Set the output mode in Weston's config file at /etc/xdg/weston/weston.ini. Under the [output] section, set mode= to the desired resolution: mode=1920x1080. Without this, Weston negotiates the best mode with the monitor via EDID. If the negotiated mode is wrong, forcing it in weston.ini is the reliable fix.

Why is the HDMI output stretched or showing wrong aspect ratio?

This happens when Weston picks a mode the monitor supports but the GStreamer pipeline is sending a different resolution. In GStreamer, add a videoscale element before waylandsink to match the pipeline output to the display resolution. Also check that the monitor's own aspect ratio setting is not overriding the signal.

Does Genio support audio over HDMI?

Yes. HDMI audio on Genio uses the ALSA HDMI audio device. In GStreamer, use the alsasink element with the HDMI device: alsasink device=hw:0,3 (device number varies by board — check aplay -l for the HDMI device index). HDMI audio requires the display to be active and the HDMI connection to be established before the audio pipeline starts.

What is the maximum HDMI resolution supported on each Genio platform?

Genio 350: HDMI 2.0, up to 4K@30fps. Genio 510: HDMI 2.0, 4K@30fps. Genio 700 and 720: HDMI 2.0, 4K@60fps. Genio 1200: HDMI 2.0, 4K@60fps with HDR10 support. The actual achievable resolution also depends on the cable (HDMI 2.0 certified cable required for 4K@60fps) and the monitor's EDID reporting.

HDMI troubleshooting on MediaTek Genio: common failures and fixes

HDMI problems on MediaTek Genio usually fall into a few categories: no signal at boot, wrong resolution negotiated via EDID, display tearing in GStreamer pipelines, or audio not working. Most have straightforward fixes once you know where Weston and the DRM driver are making decisions. For GStreamer display pipeline setup including waylandsink configuration, see the dedicated guide.

Key Insights

Weston enumerates displays at startup — connect the monitor before powering on to avoid hot-plug edge cases
Resolution is negotiated via EDID; force it in /etc/xdg/weston/weston.ini if the monitor reports a mode you do not want
The HDMI connector name in Weston is HDMI-A-1 — use this in waylandsink and weston.ini output config
HDMI audio uses ALSA — the device index varies by board, always check aplay -l first
4K@60fps requires HDMI 2.0 certified cable — a cheap cable is a common source of 4K failures

How do you check what Weston sees?

Before debugging, confirm what Weston knows about the display:

weston-info

Look for the output section. A working HDMI output looks like:

Output 0:
  name: HDMI-A-1
  description: ...
  physical_size: ...x... mm
  current mode: 1920x1080@60Hz
  modes:
    3840x2160@30Hz
    1920x1080@60Hz
    1280x720@60Hz

If HDMI-A-1 does not appear in weston-info output, Weston has not detected the display. Check physical connection and hot-plug.

Check DRM directly:

modetest -M mediatek

This lists all connectors, CRTCs, and modes the kernel DRM driver sees, independent of Weston. If modetest shows the HDMI connector as connected but Weston does not, the issue is in Weston’s startup sequencing.

What are the common HDMI failures?

No signal at all

Cause 1: Monitor connected after Weston started and hot-plug event not processed.

Disconnect and reconnect the HDMI cable. Weston handles hot-plug, but some monitors take several seconds to assert HPD. If the board has been on for a while and the display is still black, try:

weston-terminal
# or restart weston
systemctl restart weston

Cause 2: HDMI negotiated a mode the monitor cannot display.

Check kernel log for DRM mode set errors:

dmesg | grep -i hdmi
dmesg | grep -i drm

Cause 3: Board is outputting signal but monitor is on the wrong input.

Obvious, but worth checking — Genio EVKs have both DSI and HDMI. Confirm the monitor input selector.

Wrong resolution

Weston picks the highest common resolution from the monitor’s EDID. If this is wrong, override it:

vi /etc/xdg/weston/weston.ini

Add under the [core] section:

[output]
name=HDMI-A-1
mode=1920x1080

Restart Weston:

systemctl restart weston

Tearing in GStreamer video

Tearing appears when the pipeline frame rate and the display refresh rate are not synchronized. Add sync=true to waylandsink:

gst-launch-1.0 filesrc location=video.mp4 ! qtdemux ! h264parse ! mtkvdec \
  ! waylandsink display=HDMI-A-1 sync=true

For camera sources where timestamps may be inconsistent:

gst-launch-1.0 v4l2src device=/dev/video0 ! videoconvert \
  ! video/x-raw,framerate=30/1 ! waylandsink display=HDMI-A-1 sync=true

4K not working

4K requires:

HDMI 2.0 certified cable (not all cables rated for HDMI carry 4K@60fps reliably)
Genio platform that supports 4K@60fps (700, 720, 1200 — not 350 or 510 at 60fps)
Monitor that reports 4K mode in its EDID

Check if the monitor reports 4K in weston-info under modes. If it does not, the monitor or cable is the bottleneck. If it does but Weston is not using it, force the mode in weston.ini:

[output]
name=HDMI-A-1
mode=3840x2160@30

HDMI audio not working

First, identify the HDMI audio device:

aplay -l

Look for the HDMI entry, typically something like card 0: MTKAudio [MTKAudio], device 3: HDMI [HDMI].

Test directly:

aplay -D hw:0,3 /usr/share/sounds/alsa/Front_Center.wav

In GStreamer:

gst-launch-1.0 audiotestsrc ! audioconvert ! alsasink device=hw:0,3

If audio device is not listed, check that the HDMI display is active — the kernel ALSA driver for HDMI only registers the device when a display is connected and Weston has performed the mode set.

What does the display configuration matrix look like?

Platform	Max HDMI resolution	Multi-display	HDMI + DSI simultaneous
Genio 350	4K@30fps	No	No (DSI only, HDMI on some EVK revisions)
Genio 510	4K@30fps	No	No
Genio 700	4K@60fps	Yes (HDMI + DSI)	Yes
Genio 520	4K@30fps	Yes (HDMI + DSI)	Yes
Genio 720	4K@60fps	Yes (HDMI + DSI + more)	Yes
Genio 1200	4K@60fps + HDR10	Yes (up to 4 outputs)	Yes

Dealing with display bring-up issues on MediaTek Genio? ProventusNova has hands-on experience with Genio display hardware across EVK and custom board designs. See our custom board bringup service or get in touch.