Apple Thunderbolt Display with Multiple Monitors: No Daisy Chaining Mini DisplayPort Monitors

[toke lahti]

Isn't that what Apple does ? "Skating where the puck will be" ?

And you ignore that specifications are available before being fully ratified so devices can be made to "Draft" versions of specs.

How many Wifi 802.11n routers did we have before the standard was released ? Even Apple made devices for the "Draft" specification.

IEEE is much slower in ratifying than VESA, for obvious reasons.
Apple is now skating to 2009 with TB and everybody familiar with the specs including Apple have known this all the time.
Light Port was badly cutted down from original intentions, maybe just because Apple wanted to have it sooner and beeing cheaper.
They might have locked down design specs in 2009, so maybe they already knew about upcoming dp1.2, but couldn't wait for it. Another possibility was that dp version vas downgraded in 2010 when they knew that they have to settle for copper instead of fiber.

Anyway all this fuzz could have been avoided by leaving dp connector alone and putting TB to usb socket or somewhere else.

It really looks like Apple wanted TB to be just perfect for Apple's new display's and neverminding the overall problems this would cause. And surprisingly this choise gives nice opportunity for upgrade path.
Next ad campaign: 2012 models of MBP supports dp1.2 from 2009!

 

[Mikey7c8]

So, apparently the thunderbolt displays are defective. That's the unfortunate truth here, and apple needs to remedy this.

Chaining monitors was partly the excuse for the whole enterprise.

 

[aggri1]

Hi,

for those of you who might have missed this; anandtech has an in-depth review of the Thunderbolt display. One section (this page) explains why it's not possible to hook a mini-displayport monitor directly to the Thunderbolt display. Quite interesting.

Cheers,
A.

 

[AidenShaw]

So, apparently the thunderbolt displays are defective. That's the unfortunate truth here, and apple needs to remedy this.

Chaining monitors was partly the excuse for the whole enterprise.

"Defective by design" -- they meet the design spec, but the spec was a mistake.

One section (this page) explains why it's not possible to hook a mini-displayport monitor directly to the Thunderbolt display. Quite interesting.

However, it makes one wonder about what the heck the engineers were thinking of when they designed it - and reinforces the perception that bundling both PCIe and DisplayPort into the same connector was a huge mistake that will haunt Intel and Apple for years.

Fixed in TBolt 2.0 - the one with bona fide optical connectors.

Won't haunt Sony though - Sony used a special purpose connector.

 

[Mikey7c8]

Nah, I still think it was a good idea - still is - but I'm a little lost on why you'd need to add another thunderbolt controller to the chain. If the monitor doesn't have one (which seems to be the case?) one would wonder why the hell not.

 

[AidenShaw]

...but I'm a little lost on why you'd need to add another thunderbolt controller to the chain.

...because Apple believes that you won't think twice about buying a $1000 dongle to connect your old $1000 monitor to your new $1000 monitor.

Cha-ching!

 

[aggri1]

Nah, I still think it was a good idea - still is - but I'm a little lost on why you'd need to add another thunderbolt controller to the chain. If the monitor doesn't have one (which seems to be the case?) one would wonder why the hell not.

My understanding is as follows, please correct me if this is wrong.

The Apple Thunderpants Display (ATD) has a Thunderbolt chip in it which is capable of splitting out from the Thunderbolt signal(s) which it receives only one DisplayPort signal. This DP signal is used internally by the ATD. To the "output" Thunderbolt port (on the ATD) is directed only a Thunderbolt signal. The ATD has no capacity to send a DP signal to its output port, because it's using the DP signal which it split out internally.

If there is another DP signal in the TB stream, then a device further down the chain (ie attached to the ATD output port) could extract this second DP stream. Therefore, if you attach a second ATD, it can quite happily accept as input the TP signal, and extract the DP signal which it needs itself.

If you connect a device such as a Pegasus RAID and then onto that a DP monitor, the RAID can accept the TP signal as an input and split out the DP signal for use by the attached DP monitor. The DP monitor cannot accept the TP signal itself, or course (it needs the upstream TB device to split out the DP signal first).

Is this explained clearly enough? I'm not sure I'm really correct here, but it makes some kind of sense, even if it seems like rather an oversight that each TB chip could only extract one DP signal.

Clarifications/corrections welcome!

Cheers,
A.

 

[toke lahti]

I'm not sure I'm really correct here, but it makes some kind of sense, even if it seems like rather an oversight that each TB chip could only extract one DP signal.

I think this is the stupidest design for a long time.
If you wanted to have a TB display that can output video to dp display, you should build 2 TB controllers inside the TB display.
Someone really did cut the corners with this design...

I was thinking about buying a new dp display, but this makes me want to wait.
There's no other TB displays on the market and now we have a good explanation why.
Why would normal designer or engineer accept this flaw in Light Ridge?
Remains uncertain, if other display manufacturers will start manufacturing TB displays that can't chain dp displays or do they wait to get fixed TB controller.

Apple of course didn't mind about backward compability, just buy two new displays and give the old one to the poor...

 

[patent10021]

So I can connect 1 Thunderbolt display to my 2011 Mini Server then daisy chain it to the second Thunderbolt display via Thunderbolt?

HDMI doesn't work if two are connected though. I only use my HDTV for the odd MKV movie so no big deal.

Do I need to buy an extra Thunderbolt cable? How does this work?

 

[patrickcwelsh]

I agree, stupid design.