[SOLVED] MST Daisy-chain using DVI adapter

Mar 13, 2022
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I have a MSI GT 1030 with 2 video output. And I want to stop using the APU to upgrade to a CPU without integrated graphics.

I have 3 monitors and I want to use the MST (Multi-Stream Transport) from my Dell UP2716D to connect one of the two monitors. (I enabled on the configurations)

Monitor X (1280x1024 75hz) has one DVI-D input.
Monitor Y (1680x1020 75hz) has DVI-D input and D-SUB input.

I bought this adapter (Probably passive, but I'm using DVI-D to DP... I don't think that active is needed...):


Connected the adapter's displayport to the female DP output (MST) from the Dell UP2716D with both the monitors.
No image. Tried with only the Dell connected to the GT1030 and nothing connected to the APU. No image.

On the Dell's website it says:

Does the last monitor in the chain need to support DisplayPort 1.2 Multi-Stream Transport?
No, the last monitor in the chain can does not need to support DisplayPort 1.2 Multi-Stream Transport (MST).

PIP/PBP is not being used.
 
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But this website says:
"Note: ONLY the LAST monitor can be DisplayPort 1.0 or 1.1 or use an adapter. So you could have 3 DisplayPort 1.2 monitors and the last one could be connected with a standard passive DVI adaptor. "

And this:
"Alternately, you can use a DP adapter or adapter cable to convert the signal to some other standard such as HDMI. "

This Intel one say this, the others say this too if I'm not wrong:
"Daisy-chain: Monitors are connected in series. All monitors need to be daisy-chain compatible, except the last."

Wikipedia:
"Only the last display in the daisy-chain does not need to support the feature specifically or have a DP output port. "

And MST won't work as a repeater, since repeater will likely mirror that image, but this is not that case with MST,
But maybe you meant "repeater" in another way that I don't get it.

---

I think that maybe (that the MST is not working), is because the adapter works only when connecting the displayport to a input port, not to a output port... like:
DVI-D to Displayport, not Displayport to DVI-D.
I'm not precisely familiar with the DP standard, but from what I know about signaling and what the higher level overview of the DP standard is that I'm willing to scrounge up, this is why you can't use a passive DP to DVI adapter in an MST setup
  • The first thing is that the DP output must support "Dual Mode" DP to begin with. Typically this is indicated by this DP logo:
    Maybe there are some MST monitors that support this, but I'm not aware of any.
  • If the DP output is configured for DVI, then the data lines used for DP signaling are converted to output DVI instead. As mentioned, DP uses packetized data (data sent in chunks) whereas DVI uses a data stream (data sent continuously). I'm led to believe it's not possible to mix a packetized data format with a data stream.
  • The mentioning of MST acting as a repeater is meant that the signal it receives is repeated if necessary, not how the data is presented. Because data in DP is packetized, it'll have some sort of marker saying which monitor the data is meant for. Since the monitors are daisy chained, if a packet comes in that's not for the first monitor in the chain, it has to repeat this signal to the other monitors until the monitor that packet is meant for receives it, where it no longer repeats the signal.
 
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While DisplayPort does have provisions to output DVI passively, this only applies to the actual signal sources. MST is simply something that acts more like a repeater.

So you can't use DVI with MST.

EDIT: To elaborate further. DisplayPort uses packetized data while DVI uses a data stream. That is, DVI is more or less literally a digital version of VGA, which is designed to work with a CRT. The two data sending concepts are not compatible with each other. On top of this, a DP source operating in DVI mode hijacks some of the lines DP would've used for DP itself.
 
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Reactions: Crymore13
Mar 13, 2022
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10
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While DisplayPort does have provisions to output DVI passively, this only applies to the actual signal sources. MST is simply something that acts more like a repeater.

So you can't use DVI with MST.
But this website says:
"Note: ONLY the LAST monitor can be DisplayPort 1.0 or 1.1 or use an adapter. So you could have 3 DisplayPort 1.2 monitors and the last one could be connected with a standard passive DVI adaptor. "

And this:
"Alternately, you can use a DP adapter or adapter cable to convert the signal to some other standard such as HDMI. "

This Intel one say this, the others say this too if I'm not wrong:
"Daisy-chain: Monitors are connected in series. All monitors need to be daisy-chain compatible, except the last."

Wikipedia:
"Only the last display in the daisy-chain does not need to support the feature specifically or have a DP output port. "

And MST won't work as a repeater, since repeater will likely mirror that image, but this is not that case with MST,
But maybe you meant "repeater" in another way that I don't get it.

---

I think that maybe (that the MST is not working), is because the adapter works only when connecting the displayport to a input port, not to a output port... like:
DVI-D to Displayport, not Displayport to DVI-D.
 
Last edited:
The use of adapters depends on the device. On my U2414H, no type of adapter worked from an MST output. On my UP2516D, active DP to DVI/HDMI adapters worked, but not passive. On my Accell MST hub, both active and passive adapters worked.

The UP2716D should be the same as the UP2516D, so I think you will need an active adapter, not a passive one.
 
Reactions: Crymore13
Mar 13, 2022
3
0
10
0
The use of adapters depends on the device. On my U2414H, no type of adapter worked from an MST output. On my UP2516D, active DP to DVI/HDMI adapters worked, but not passive. On my Accell MST hub, both active and passive adapters worked.

The UP2716D should be the same as the UP2516D, so I think you will need an active adapter, not a passive one.
I will try to purchase on active adapter, cheaper than buy another graphics card.

Thanks!
 
But this website says:
"Note: ONLY the LAST monitor can be DisplayPort 1.0 or 1.1 or use an adapter. So you could have 3 DisplayPort 1.2 monitors and the last one could be connected with a standard passive DVI adaptor. "

And this:
"Alternately, you can use a DP adapter or adapter cable to convert the signal to some other standard such as HDMI. "

This Intel one say this, the others say this too if I'm not wrong:
"Daisy-chain: Monitors are connected in series. All monitors need to be daisy-chain compatible, except the last."

Wikipedia:
"Only the last display in the daisy-chain does not need to support the feature specifically or have a DP output port. "

And MST won't work as a repeater, since repeater will likely mirror that image, but this is not that case with MST,
But maybe you meant "repeater" in another way that I don't get it.

---

I think that maybe (that the MST is not working), is because the adapter works only when connecting the displayport to a input port, not to a output port... like:
DVI-D to Displayport, not Displayport to DVI-D.
I'm not precisely familiar with the DP standard, but from what I know about signaling and what the higher level overview of the DP standard is that I'm willing to scrounge up, this is why you can't use a passive DP to DVI adapter in an MST setup
  • The first thing is that the DP output must support "Dual Mode" DP to begin with. Typically this is indicated by this DP logo:
    Maybe there are some MST monitors that support this, but I'm not aware of any.
  • If the DP output is configured for DVI, then the data lines used for DP signaling are converted to output DVI instead. As mentioned, DP uses packetized data (data sent in chunks) whereas DVI uses a data stream (data sent continuously). I'm led to believe it's not possible to mix a packetized data format with a data stream.
  • The mentioning of MST acting as a repeater is meant that the signal it receives is repeated if necessary, not how the data is presented. Because data in DP is packetized, it'll have some sort of marker saying which monitor the data is meant for. Since the monitors are daisy chained, if a packet comes in that's not for the first monitor in the chain, it has to repeat this signal to the other monitors until the monitor that packet is meant for receives it, where it no longer repeats the signal.
 
Reactions: Crymore13

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