Hdmi problem

Hi Sam

Still my hdmi dropouts problem using 4k 10 bits uhd hdr files.
It s working when using an Hdmi amplifier between the vero4k and my projector.
It doesn’t work when going through my Yamaha receiver (2060)…
I 've very good HDMI 18gbps certified cables.
Is It not a problem with the HDMI PHY of the vero 4k?



There is indeed a limited drive strength of the HDMI PHY on Vero 4K. With my Vero 4K, I can get 10M to my projector. However I usually use an AV receiver and this amplifies the signal strength.

What distance are you trying to cover?
Can you show me dmesg when you have signal problems? A bad cable sometimes shows a lot of HPDs and I have seen this before with my Optoma where the projector will keep trying to negotiate.



Vero4k To receivrr is 3m long.
Receiver To jvc5000 is 15m long…
I use a feintech hdmi amplifier. It works Nice when between vero4k and the beamer.
It fails when using my rx-2060 receiver.

Is It possible to remove the limited drive strength of the HDMI phy on vero4k?
I will post dmesg tomorrow when I’m at home

Thanks Sam!

The drive strength should be adequate.
3M is not substantial, and if Vero 4K is doing its job, then the AV receiver will reflect this and show a signal (audio and video).

What happens after the receiver isn’t really the Vero 4K’s responsibility, and something else may be at play here.

I had a similar problem with a Pi years ago, but changing the HDMI cable resolved the issue.
Sometimes, even ignoring HPD events and forcing a lock is enough to solve the problem over
long distances.

What is HPD?

Here is my dmesg:

[ 75.027805] 2160p24hz 2997 125
[ 75.027808] 2160p24hz 2997 125
[ 75.027810] hdmtix: set audio
[ 75.027819] hdmitx tx_aud_src = 0
[ 75.027843] hdmitx: fs = 2, cd = 5, tmds_clk = 296703
[ 75.027845] hdmitx aud_n_para = 4459
[ 75.027861] hdmitx set channel status
[ 75.027918] hdmitx: audio: Audio Type: PCM
[ 75.027920] hdmtix: set audio
[ 75.027927] hdmitx tx_aud_src = 0
[ 75.027950] hdmitx: fs = 2, cd = 5, tmds_clk = 296703
[ 75.027951] hdmitx aud_n_para = 4459
[ 75.027967] hdmitx set channel status
[ 75.028022] hdmitx: audio: Audio Type: PCM
[ 75.028121] Start = 0x10000100 End = 0x100001ff
[ 75.028131] [0x10000104]: 0x00000001
[ 75.028315] [0x10000180]: 0x000000ff
[ 75.028317] [0x10000181]: 0x000000ff
[ 75.028320] [0x10000182]: 0x00000003
[ 75.028322] [0x10000183]: 0x00000007
[ 75.028325] [0x10000184]: 0x0000003f
[ 75.028328] [0x10000185]: 0x00000002
[ 75.028332] [0x10000187]: 0x000000ff
[ 75.028335] [0x10000188]: 0x00000003
[ 77.557954] hdmitx: system: irq 80000004
[ 77.557994] hdmitx: plugout
[ 77.558012] hdmitx: system: unmux DDC for gpio read edid
[ 77.558019] hdmitx: clear RX hdr info
[ 81.413149] hdmitx: system: irq 80000002

Full log might give more clues; but there does indeed to be a hotplug event there.

It would be interesting to know if runninig echo hpd_lock1 > /sys/class/amhdmitx/amhdmitx0/debug​ at startup helps

I Will try.
How To post full logs ?
Too much lines…


Vero4k in 8bits ok
The problem is using 10 bits

Did you try the hpd command?
What makes you think the issue is related to 10-bit content only? Should this be the case: then it would mean an HDMI cable between the Vero to the projector (including AV) may not be up to spec

Yes I try the hpd command.
But don’t work.

I 've not this problem when removing the 10bit command in /etc/rc.local

HDMI cable is ok I think because all is ok in 10bits 4k HDR when plugging the cable between vero4k and projector.
It doesn’t work anymore when I plug the Yamaha rx-a2060 in the line.

Thanks for clarifying

Did you search about this receiver? It seems it won’t accept 10-bit signals in certain modes / zones.
Try 10-bit with another device.


Will look further.
Mode1 on Yamaha receiver is ok for 4k full HDR 4:4:4…

OSMC probably doing 420.
I saw some comments about the receiver not handling that.


444 is not possible for osmc?

It’s automatic.


Using the hpd lock command is working !
How to do now to do this command automatic?
In rc.local?



I’m glad to hear this works.
You can edit rc.local with:

sudo nano /etc/rc.local

And add the hpdlock command before exit 0.