Thunderbolt Display to 30" Cinema Display

[SPNarwhal]

I saw the thread asking about multiple displays, I know. but that seemed to be a DVI to DVI issue?

I just got a 27" Thunderbolt Display, and I connected my 30" Cinema Display (with a Dual Link DVI to Mini Display Port adapter) and the 30" won't show up as anything.

I read a post that was from 2011 about Thunderbolt display not being able to daisy-chain to a Cinema display, but that was, again, from 2011. Assuming they fixed this in a firmware update? Or have they not?

Am I out of luck here?

I don't see why it wouldn't work.

 

[Bear]

They may not have changed that. Have you tried the Cinema Display and adapter directly into a Thunderbolt port to make sure that it's working correctly?

 

[jdaniel]

you cannot connect a cinema display to a TB display.....you cannot connect a TV via a mini display port to hdmi cable.. either...I have read extensively about this......even from apple's info on the TB display page direct connection is a DEF NO.. no way.... now.. if you have a HD drive or something or other connecting to the back of the TB display and you connect a display to that device.. IT MAY WORK BUT NO ONE IS EVER CLEAR ABOUT IT.. if you are in the US and you can buy and return stuff without penalty I would try but TB devices are expensive and not something you would buy unless you need it.

 

[SPNarwhal]

They may not have changed that. Have you tried the Cinema Display and adapter directly into a Thunderbolt port to make sure that it's working correctly?

I did. I've had my 30" connected to my thunderbolt out port on my Macbook Pro for the last 2 years.

As for not working, I don't understand. Why would Apple refuse to permit that? Seems so strange to me.

 

[thekev]

I did. I've had my 30" connected to my thunderbolt out port on my Macbook Pro for the last 2 years.

As for not working, I don't understand. Why would Apple refuse to permit that? Seems so strange to me.

It has nothing to do with permission. It's not supported at a hardware level. The original thunderbolt spec only supports daisy chaining with thunderbolt. Run in displayport only mode, it's equivalent to displayport 1.1a, which also doesn't support daisy chaining. Thunderbolt 2 MIGHT at some point, because it's supposed to support displayport 1.2. Displayport 1.2 supports separate streams, although I don't know of any hardware that supports daisy chaining as of yet. Right now I am only aware of an expensive hub that won't work with thunderbolt as stated. I don't know whether it works properly under OSX or if dual link dvi will work as expected, but the bandwidth is there. So far according to Apple the only things with thunderbolt 2 are the retina macbook pro and the upcoming mac pro. I'm surprised they mention 4K displays when they don't offer one as of yet.

Anyway right now the only way you can do this is by running them on completely different ports.

 

[brand]

As for not working, I don't understand. Why would Apple refuse to permit that? Seems so strange to me.

Why are people always think that Apple intentionally keeps them from doing certain things without even bothering to research the technology and problem first.

 

[SPNarwhal]

Why are people always think that Apple intentionally keeps them from doing certain things without even bothering to research the technology and problem first.

Figured that the thunderbolt port acted as the same thunderbolt port on the Macbook itself, which acts as a display output. I know that the thunderbolt port on the Thunderbolt Display works as a display output as well, but apparently only with another thunderbolt display.

It makes sense to assume it would work.

 

[priitv8]

The original thunderbolt spec only supports daisy chaining with thunderbolt.

True, but wasn't it so, that the mDP device is allowed at the end of the chain? Because TB controller has to switch over to DP compatibility mode upon detecting a DP device (reuse of connector pins), it can do it only at the very last controller without breaking the chain.

Compatibility to DisplayPort devices is provided by an interoperability mode between host devices and DisplayPort products; if a DisplayPort device is detected, a Thunderbolt controller will drive compatibility mode DisplayPort signals to that device.

Source

So I reckon, the TB controller in ATD has no DP compatibility mode (or has it disabled).

 

[cube]

DisplayPort 1.1 does not support monitor daisy chaining.

Blame Apple for endorsing Thunderbolt 1 when DisplayPort 1.2 already existed.

 

[thekev]

True, but wasn't it so, that the mDP device is allowed at the end of the chain? Because TB controller has to switch over to DP compatibility mode upon detecting a DP device (reuse of connector pins), it can do it only at the very last controller without breaking the chain.

It doesn't work off something like a monitor. If you're talking about a hub of some sort that can specifically split off mini - displayport. Nothing has ever worked off the thunderbolt display. When it came out Macworld claimed the old 27" cinema worked chained off the Pegasus R6, but I haven't personally seen anyone set that up.

 

[paulrbeers]

I saw the thread asking about multiple displays, I know. but that seemed to be a DVI to DVI issue?

I just got a 27" Thunderbolt Display, and I connected my 30" Cinema Display (with a Dual Link DVI to Mini Display Port adapter) and the 30" won't show up as anything.

I read a post that was from 2011 about Thunderbolt display not being able to daisy-chain to a Cinema display, but that was, again, from 2011. Assuming they fixed this in a firmware update? Or have they not?

Am I out of luck here?

I don't see why it wouldn't work.

Just add a thunderbolt hard drive after the Thunderbolt Display then hang the MDP to dual dvi cable off the hard drive. This will work just fine

 

[priitv8]

Just add a thunderbolt hard drive after the Thunderbolt Display then hang the MDP to dual dvi cable off the hard drive. This will work just fine

Doesn't this prove, that the TB controller inside ATD just lacks the DP Compatibility mode (for whatever reason)?

 

[paulrbeers]

Doesn't this prove, that the TB controller inside ATD just lacks the DP Compatibility mode (for whatever reason)?

Anandtech proved how this works back in 2011. This has been covered 1000 times in this forum: http://www.anandtech.com/show/4832/the-apple-thunderbolt-display-review/8