HP Pavilion Power 580-137c has three HDMI outputs, only one works?

[Steorn]

Hey ya'll, subject says most of it. How and why don't these two ports work, and how do I get them to. The product is advertised as having 5 multi-monitor support but notes it "may require an active adapter", which makes no sense to me, if it's referring to the two inactive HDMI ports. Can I get the gpu to support these outputs??

 Unless this is fixed I'll have to make do buying a Displayport cable, but I'm not happy about it. 

[banhien · Accepted solution]

@Steorn 

Its specs

   https://support.hp.com/au-en/document/c05686933

which says

    The Basswood motherboard does not support integrated graphics.

Therefore two HDMI ports on the motherboard won't work. It has 3 HDMI ports:

• One from AMD Radeon RX 550 video card
• Two from motherboard

and the following 2 ports won't work

Figure : Basswood back I/O panel

1. USB 2.0: 2
2. LAN (Ethernet)
3. HDMI out: 2
4. USB 3.0: 2
5. Audio: Line in
6. Audio: Line out
7. Audio: Microphone

You can connect up to 5 monitors BUT the specs says "Full multi display support might require an active adapter." but at least you can use  DL-DVI + HDMI + DisplayPort ports on the AMD Radeon RX 550 video card.

Hope this explains why ONLY one HDMI port is working.

Regards.