Displayport-HDMI cable strange behaviour

[balint.madarasz]

So i got a new pc along these lines:
Kontron KTQM87(its a mobo with an integrated intel i7 4860EQ and an iris pro 5200)
8 gigs of hyperx blue 1600mhz ram
Bitfenix whisper 450w
and i already have a LG 24MP55.

My motherboard has 3 Displayport 1.2 outputs. I red the manual which stated that it supports a passive Displayport-HDMI adatper so i got a maleDP-maleHDMI cabel.(My monitor has 1 HDMI and 1 DSUB port).
When i connect my pc to the monitor i get no signal. The HDMI port on my monitor works, it's hooked up to my older pc right now. The curious part is that if i use a HDMI-DVI adapter on the HDMI end of the cabel and connect it to my brother's monitor using the DVI end everything works fine.
Sadly i dont have a femaleDVI-maleDSUB adapter on hand. I restarted everything numerous times and checked if all the cabels are pluged in correctly.

TLDR: DP port on monitor->DP-HDMI cabel->HDMI port on monitor= NO SIGNAL
DP port on monitor->DP-HDMI cabel->HDMI-DVI adapter->DVI port on monitor = WORKS

 

[alexoiu]

"I red the manual which stated that it supports a passive Displayport-HDMI adatper '
The dual mode dp was a standard starting with 1.3. So not sure if the ports on the board are dual mode.
An active adapter would probably solve the issue.
HDMI to DVI cable does work with no issues.
DVI to D-SUB passive adapter does work only if DVI-I. For DVI-D, an active adapter is needed.

 

[balint.madarasz]

"I red the manual which stated that it supports a passive Displayport-HDMI adatper '
The dual mode dp was a standard starting with 1.3. So not sure if the ports on the board are dual mode.
An active adapter would probably solve the issue.
HDMI to DVI cable does work with no issues.
DVI to D-SUB passive adapter does work only if DVI-I. For DVI-D, an active adapter is needed.

But if it needs an active dp-hdmi adapter why does it work if i add an extra hdmi-dvi adapter?

 

[alexoiu]

Then it might be a HDMI cable issue.

 

[Glenwing]

Dual-Mode DisplayPort has been almost universally supported for years, though it is technically an optional feature on DP 1.2 and below it's supported by almost any device. It's not something you need to worry about.