HDMI Issue

gaborkurucz — Thu, 12 Apr 2018 09:24:18 GMT

Hi,

I'm trying to bring up a custom designed board based on the Solid-Run Hummingbird Edge. Unfortunately I have encountered some issues with HDMI.
With the original HB EDGE I can see everything on the screen after powering on the board. With my board the display is blank until linux boots up, then all is fine. However if I unplug the HDMI conenctor, after plugging back the display remains blank. I have to restart the board to have anything on the screen again.

dmesg shows the followings (when replugging)
"
56.840202] mxc_hdmi 20e0000.hdmi_video: same edid
[ 56.840300] mxc_hdmi 20e0000.hdmi_video: mxc_hdmi_cable_connected reports HDMI mode
"
Is there any idea what could be the problem ?

When designing the board I've tried to calculate impedances / route the traces according to the HDMI standards. The length of the traces are around 22mm, +/- 0.2mm each.

Thanks

Re: HDMI Issue

igorpadykov — Thu, 12 Apr 2018 23:21:17 GMT

Hi Gabor

one can test it with i.mx6q nxp sabre sd reference board to check if this depends

on hardware with nxp official bsps described on

i.MX Software|NXP

HPD issue was described on some third party boards:

DVI Support on i.MX6 boards - Boundary Devices

Best regards
igor
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