topic No Output on HDMI Signal for IMX8MP in i.MX Processors

No Output on HDMI Signal for IMX8MP

bc_th — Wed, 02 Aug 2023 12:46:55 GMT

Hi everyone,

my team and I are using a 7" display from Actron (Model No. ETML070023UDRA, Resolution 800x480@60) and a Phytec i.MX8MP board running a Yocto system (Yogurt Vendor xwayland (Phytec Vendor Distribution) BSP-Yocto-FSL-i.MX8MP-PD21.1.3).

The display works fine when we plug it in on a laptop and the board also correctly displays output on our monitors (benq) but when we connect the display with the board it does not react at all.

xrandr and xrandr --listmonitors only prints "Can't open Display"

We've also tried setting the mode within the /etc/xdg/weston/weston.ini file and restarting weston/ the board but that did not have any effect either.

[output] name=HDMI-A-1 mode=800x480

Another idea we tried is updating the u-boot environment via:

env set video HDMI-A-1:800x640M@60D env save boot

But that did not have any effect on the system. We also tried different options like the following with no luck either.

env set video mxcfb0,dev=hdmi,800x480@60,if=RGB24

Does anyone have any ideas what we missed or what we can try? We can also provide further information if needed. Thanks in advance!

Re: No Output on HDMI Signal for IMX8MP

joanxie — Wed, 02 Aug 2023 14:22:37 GMT

pls share the logfile and give me the result when you use command dmesg | grep drm

Re: No Output on HDMI Signal for IMX8MP

bc_th — Thu, 03 Aug 2023 05:04:55 GMT

This is the log you mentioned

[ 4.062709] imx-drm display-subsystem: trying to bring up master [ 4.062714] imx-drm display-subsystem: Looking for component 0 [ 4.062721] imx-drm display-subsystem: Looking for component 1 [ 4.062732] imx-drm display-subsystem: found component imx-lcdifv3-crtc.1, duplicate 0 [ 4.062739] imx-drm display-subsystem: Looking for component 2 [ 4.062745] imx-drm display-subsystem: Looking for component 3 [ 4.062879] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 4.069525] [drm] No driver support for vblank timestamp query. [ 4.075490] imx-drm display-subsystem: binding imx-lcdifv3-crtc.0 (ops lcdifv3_crtc_ops) [ 4.075538] imx-drm display-subsystem: bound imx-lcdifv3-crtc.0 (ops lcdifv3_crtc_ops) [ 4.083489] imx-drm display-subsystem: binding imx-lcdifv3-crtc.1 (ops lcdifv3_crtc_ops) [ 4.083556] imx-drm display-subsystem: bound imx-lcdifv3-crtc.1 (ops lcdifv3_crtc_ops) [ 4.091511] imx-drm display-subsystem: binding 32c00000.bus:ldb@32ec005c (ops imx8mp_ldb_ops) [ 4.098185] imx-drm display-subsystem: bound 32c00000.bus:ldb@32ec005c (ops imx8mp_ldb_ops) [ 4.106620] imx-drm display-subsystem: binding 32fd8000.hdmi (ops dw_hdmi_imx_ops) [ 4.126191] imx-drm display-subsystem: bound 32fd8000.hdmi (ops dw_hdmi_imx_ops) [ 4.134412] [drm] Initialized imx-drm 1.0.0 20120507 for display-subsystem on minor 1 [ 4.525235] imx-drm display-subsystem: HDMI-A-1: EDID is invalid: [ 4.706411] imx-drm display-subsystem: fb0: imx-drmdrmfb frame buffer device

Re: No Output on HDMI Signal for IMX8MP

joanxie — Thu, 03 Aug 2023 07:11:09 GMT

did you use nxp bsp or your own SW? refer to your logfile:

imx-drm display-subsystem: HDMI-A-1: EDID is invalid:

for HDMI, you don't need add this in the uboot, pls share dtb file you use and tell me what pixel clock of your HDMI you use

Re: No Output on HDMI Signal for IMX8MP

bc_th — Thu, 03 Aug 2023 11:24:12 GMT

We fixed the issue. The default mode line that we got from connecting the display to the board was incorrect.
We created a mode with

cvt 800 480 60

and then put the whole resulting String into the weston.ini so it looks like this:

[output] name=HDMI-A-1 mode=29.50 800 824 896 992 480 483 493 500 -hsync +vsync

After a restart the board could interact with the display via HDMI.

Thanks for the previous help!