imx8mqevk doesn't have HDMI signal to some monitors

[harry_cheng]

Hi,

I'm working on an imx8mqevk. It works well, but there is no display when I connect it to some monitors, and the monitors say something like "HDMI no signal".

I tried an image "fsl-image-qt5-validation-imx-imx8mqevk" built for xwayland, and an image build for wayland. The results are same.

There are already some people talking about similar issues, such as:
https://community.nxp.com/thread/471004
https://community.nxp.com/thread/470325
But my issue doesn't look like related to bootargs. If I stop uboot and try something like "printenv", there is something displayed on "good" monitors, but it's still "no signal" on "bad" monitors. Also I tried adding "video=HDMI-A-1:1920x1080-32@60" in bootargs, and it didn't help.

Some raspberrypi users fixed their HDMI issues by configuring their build to force stronger HDMI signal. I couldn't find similar configurations for yocto.

I tried xrandr with my xwayland image. It finds XWAYLAND0 as the monitor, and can't get information of the real monitor even if there is a "good" one connected.

root@imx8mqevk:~# xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
XWAYLAND0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 480mm x 270mm
1920x1080 59.96*+
root@imx8mqevk:~#

Thank you for reading the question. Any advice is appreciated.

[yashavanthashet]

Hi Harry,

Is your board boots fully if HDMI cable is not connected while booting when HDMI is enabled source.

Regards,

Yashavantha

[harry_cheng]

Yes, the board boots even without HDMI cable connection. I can ssh to it and do my normal things. Although something weird might happen if I run a gstreamer pipeline, but I'm not really concerned with it now.

[lingguan]

Hello,

    This is my dmesg.

[harry_cheng]

I read your question, it looks different with mine, because I don't have display even in u-boot while you have it.

Boris' suggestion to upgrade the kernel might be a good solution for you.

Perhaps you can also consider trying a different monitor. As Diego said, not all monitors are supported.

[lingguan]

Thank you , I'll give it a try.

[diegoadrian]

Hello, 

Like everyone is saying, not all the HDMI monitors are supported by the i.MX8M. This is due to the frequency operation of the monitor is not the one that is supported by the driver of the i.MX. You could try to change the driver to make work the monitor that you are willing to use. However this is to difficult to make, I recommend you to contact professional service support, they could help you with that.

Best Regards,

Diego.

[harry_cheng]

Thanks for your answer, Diego.

I agree with what you said. It's just not ideal when some monitors work with imx6 but don't work with imx8.

[harry_cheng]

I downloaded the prebuilt image L4.9.88_2.0.0_images_MX8MQ.tar.gz, and wrote it to a sdcard:
$ sudo dd if=fsl-image-qt5-validation-imx-xwayland-imx8mqevk.sdcard of=/dev/sdd bs=1M && sync
Then I still got exactly the same result.

[bu0507870 · Accepted solution]

Hello.

In my case (too works only on some FullHD monitors) helps switch to use 4.9.123 kernel:

> repo init -u https://source.codeaurora.org/external/imx/imx-manifest -b imx-linux-rocko -m imx-4.9.123-2.3.0-8mm_ga.xml
> ...
> DISTRO=fsl-imx-wayland MACHINE=imx8mqevk source fsl-setup-release.sh -b build-wayland
> ...

[harry_cheng]

4.9.123 fixed display on some monitors. Although there is still problem with other monitors, it's a good improvement.

Thanks again for you help.

[harry_cheng]

Thank you, Boris. I'll give it a try.

[harry_cheng]

Here is a list of monitors/TVs we have tried so far:

1. works with imx8 through HDMI:
Samsung UN32J5205, 1080p TV
Spectre E24, 1080p TV
AG Neovo TM-23, 1080p touchscreen
AOC U2868PQU, 4K
Asus VW246H, 1080p

2. works with imx8 through HDMI/DVI adapter:
AOC E2425SWD, 1080p, DVI

3. "no signal" with imx8 through HDMI, but work with imx6:
ASUS VE228H, 1080p
ASUS VE247, 1080p

4. ""no signal" with imx8 through HDMI/DVI adapter, but work with imx6:
Iiyama ProLite T1731SR 1280x1024 touchscreen
Iiyama ProLite T1931SR 1280x1024 touchscreen
LG 22M37D, 1080p
LG Flatron W2042TQ-BF, 1680 x 1050
ASUS VE247, 1080p