Caldigit TS4 Dock

[joevt]

Is there anyway with the EDID to force a screen to not use more than HBR?

Probably not. A display will use the maximum link rate that both it and the source supports. With Thunderbolt the maximum link rate may be affected by other displays connected to it or by the Thunderbolt cable.

You could use a DisplayPort cable with fewer lanes. For example, a USB-C dock that supports USB 3.x will have only 2 lanes of DisplayPort instead of 3.

Should I care if the screen selects YUV 422 sometimes? It seems that MacOS tends to favor this mode which is how it achieves 60Hz on a 2560x2880 in HBR mode.

4:2:2 reduces the color resolution horizontally by half. Grayscale resolution (for black & white text) is unaffected.

4:2:2 HBR can do 346MHz at 10bpc and 432MHz at 8bpc. That doesn't seem like enough. What does SwitchResX say the pixel clock is for that mode?
The minimum pixel clock for 2560x2880@60Hz is 442.368 MHz but that's impossible since that excludes the horizontal and vertical blanking.
Are you sure it's not using 4:2:0 ?

4:2:2 HBR can do 432MHz at 10bpc and 540MHz at 8bpc.

 

[davewolfs]

 

[davewolfs]

I am going based on the above. If disabled 420 in EDID it goes back to RGB and I am getting the same rates as my PC. Eg max 360Mhz with 8BPC.

 

[davewolfs]

Am I better off with RGB and Lower refresh rate or non rgb color format?

 

[joevt]

I am going based on the above.

I looked up the wrong numbers. I've updated my previous post.

If disabled 420 in EDID it goes back to RGB and I am getting the same rates as my PC. Eg max 360Mhz with 8BPC.

Right. 360Mhz for 8bpc is the limit for HBR when DSC is unavailable and chroma subsampling is disabled.

Am I better off with RGB and Lower refresh rate or non rgb color format?

I think people prefer higher refresh rate over color fidelity. Like I said before, you shouldn't see an issue with gray scale text. Only the color between two horizontally adjacent pixels of differing colors is affected.

 

[davewolfs]

I looked up the wrong numbers. I've updated my previous post.


Right. 360Mhz for 8bpc is the limit for HBR when DSC is unavailable and chroma subsampling is disabled.


I think people prefer higher refresh rate over color fidelity. Like I said before, you shouldn't see an issue with gray scale text. Only the color between two horizontally adjacent pixels of differing colors is affected.

So why all these crazy posts of people jumping through hoops to get RGB enabled?

As for DSC - I had to lock onto DP 1.2 to prevent the system from using HBR3 if it powered on first.

Not sure if there is a way to turn on DP 1.4 but have it be max HBR2. It’s silly that the Dock would choose HBR3 since it’s impossible for the Display to reach this.

 

[joevt]

So why all these crazy posts of people jumping through hoops to get RGB enabled?

Because the RGB mode in there case can do full refresh rate while in your case it cannot?

 

[joevt]

As for DSC - I had to lock onto DP 1.2 to prevent the system from using HBR3 if it powered on first.

Do either of the displays you mentioned support DSC?
If the display was not set to DP 1.2 then could it then use 4:2:0?

Not sure if there is a way to turn on DP 1.4 but have it be max HBR2. It’s silly that the Dock would choose HBR3 since it’s impossible for the Display to reach this.

I'm confused. Which display are you referring to? Why do you want DP 1.4 but have it max HBR2?
Isn't the problem that the LG 40WP95C does reach HBR3 and requires HBR3 for full resolution and refresh rate?

I wonder if you could connect a DP 1.2 MST hub to limit the display to HBR2?
Or connect a DP 1.4 MST hub that supports DSC to convert HBR2 + DSC to HBR3?

If you connect a USB-C dock, then the bandwidth will be limited to 2 lanes of HBR3. That's 75% of HBR2 - enough for 540 MHz 8bpc or 432 MHz 10bpc.
The CalDigit SOHO is a USB-C dock that has an MST hub that supports DSC but it can't decompress 10bpc. I don't know if any MST hubs can decompress 10 bpc. 10 bpc is required for HDR.

 

[davewolfs]

Here is the problem with the TS4.

It has no concept of connect order for any display plugged in when coming out of sleep mode. It will usually try to connect on the DisplayPort first but this doesn’t work when in sleep mode.

So what happens is the first display coming out of sleep will lock on HBR3. In this case that is the DualUp. When this happens the 40WP will run at 30Hz.

The only solution that I have is to force the DualUp into display port 1.2 to limit it to HBR2 so that when things mess up with sleep the 40WP can still do 60Hz in 8 bpc RGB or 72Hz with ycbcr.

Do either of the displays you mentioned support DSC?
If the display was not set to DP 1.2 then could it then use 4:2:0?


I'm confused. Which display are you referring to? Why do you want DP 1.4 but have it max HBR2?
Isn't the problem that the LG 40WP95C does reach HBR3 and requires HBR3 for full resolution and refresh rate?

I wonder if you could connect a DP 1.2 MST hub to limit the display to HBR2?
Or connect a DP 1.4 MST hub that supports DSC to convert HBR2 + DSC to HBR3?

If you connect a USB-C dock, then the bandwidth will be limited to 2 lanes of HBR3. That's 75% of HBR2 - enough for 540 MHz 8bpc or 432 MHz 10bpc.
The CalDigit SOHO is a USB-C dock that has an MST hub that supports DSC but it can't decompress 10bpc. I don't know if any MST hubs can decompress 10 bpc. 10 bpc is required for HDR.

 

[davewolfs]

@joevt Will all USB-C docks be limited to 2 lanes or is that a Soho thing?

 

[joevt]

A USB-C cable has four Super Speed lines. If two are used for USB 3.x, then only 2 remain for DisplayPort. See DisplayPort Alt Mode.
https://en.wikipedia.org/wiki/USB-C
https://en.wikipedia.org/wiki/DisplayPort

You can get a USB-C dock that has four lanes of DisplayPort, but in that case, the USB-C cable has only the High Speed lines remaining for USB 2.0.
https://www.cablematters.com/pc-899...-20-480-mbps-ethernet-and-power-delivery.aspx

Some displays with USB-C inputs have a switch in their onscreen menu to switch between USB 3.x + 2 lanes of DisplayPort and USB 2.0 + 4 lanes of DisplayPort.
Here's an adapter with a switch:
https://www.store.level1techs.com/products/p/dp-repeater-hdmi-splitter-6sha9-yznx5-zm58w

 

[davewolfs]

@joevt a dock with four lanes of display port (the above cable matters) would mean 4 lane HBR3 right?

 

[joevt]

@joevt a dock with four lanes of display port (the above cable matters) would mean 4 lane HBR3 right?

If it's a DisplayPort 1.4 dock, yes.

A DisplayPort 1.2 dock is limited to HBR2.

 

[davewolfs]

@joevt oddly on MacOS when one display is connected at HB3 the Soho (when plugged into the TS4) cannot exceed RBR speeds. Odd because it can do HBR speeds when nothing is plugged in.

Has to be a limitation on the total TS4 speed. Maybe it is picking up on the ports. Also the lanes remained at 4.

 

[davewolfs]

.

 

[joevt]

@joevt oddly on MacOS when one display is connected at HB3 the Soho (when plugged into the TS4) cannot exceed RBR speeds. Odd because it can do HBR speeds when nothing is plugged in.

Has to be a limitation on the total TS4 speed. Maybe it is picking up on the ports. Also the lanes remained at 4.

The SOHO contains a DisplayPort MST hub. The MST hub takes two lanes and can convert that to 4 lanes. It can also accept DSC and decompress it (but not for 10bpc).

If a display is connected at HBR3 speed to a TS4 dock, then only HBR x4 remains for the SOHO connected to the same dock. The SOHO is limited to two lanes, so it should be able to accept HBR2 x2 which is equivalent to HBR x4. I don't know if macOS is smart enough for that. If it limits the SOHO to HBR x2, then it would be limited to 83% of RBR x4.

If you had an Intel Mac then AllRez would be able to show all the DisplayPort info, including info about the MST hub using https://github.com/joevt/AllRez
I don't know how to get the same info on Apple Silicon Macs.

 

[davewolfs]

It was worth a try. Thanks for your help.

I am getting DisplayPort info from the debug screen on the monitor. It’s available if turning on in service mode.

 

[macphoto861]

Having a few pesky USB problems come up recently. Unfortunately, I made three substantial changes pretty much simultaneously (moved from Monterey to Sonoma, moved from M1 Max to M3 Max, and updated the TS4 firmware), so I don't know which of these triggered the issues. Here's what's happening:

1) I have a 4-port USB hub through which several USB2 devices are attached (DVD burners and speakers), and these devices disappear after a while (not sure of the exact time span). When it first happened, I assumed the hub had gone bad, so I replaced it with another one I had on hand, but then a day or two later I noticed it had done the same thing. Put the original one back, and it worked... turns out just unplugging/replugging the hub brings those devices back online, but this problem did not happen with my previous setup (M1 Max, Monterey, original TS4 firmware).

2) A different 4-port USB hub last night had a different problem... I noticed that a copy operation to a fast USB3 flash drive was taking a long time, and upon investigating, saw that it was only connected as a USB2 (480gb) device. Unplugging/replugging the flash drive yielded the same connection, but unplugging/replugging the hub restored full USB3 speed. This has only happened once, but I haven't used this particular hub enough to know if it's truly a recurring problem like #1, or was just a one-time fluke.

 

[xraydoc]

Here is the problem with the TS4.

It has no concept of connect order for any display plugged in when coming out of sleep mode. It will usually try to connect on the DisplayPort first but this doesn’t work when in sleep mode.

So what happens is the first display coming out of sleep will lock on HBR3. In this case that is the DualUp. When this happens the 40WP will run at 30Hz.

The only solution that I have is to force the DualUp into display port 1.2 to limit it to HBR2 so that when things mess up with sleep the 40WP can still do 60Hz in 8 bpc RGB or 72Hz with ycbcr.

My two Studio Displays connected through my TS4 never change places. But they are Apple displays, so…

 

[dstyp]

Having a few pesky USB problems come up recently. Unfortunately, I made three substantial changes pretty much simultaneously (moved from Monterey to Sonoma, moved from M1 Max to M3 Max, and updated the TS4 firmware), so I don't know which of these triggered the issues. Here's what's happening:

1) I have a 4-port USB hub through which several USB2 devices are attached (DVD burners and speakers), and these devices disappear after a while (not sure of the exact time span). When it first happened, I assumed the hub had gone bad, so I replaced it with another one I had on hand, but then a day or two later I noticed it had done the same thing. Put the original one back, and it worked... turns out just unplugging/replugging the hub brings those devices back online, but this problem did not happen with my previous setup (M1 Max, Monterey, original TS4 firmware).

2) A different 4-port USB hub last night had a different problem... I noticed that a copy operation to a fast USB3 flash drive was taking a long time, and upon investigating, saw that it was only connected as a USB2 (480gb) device. Unplugging/replugging the flash drive yielded the same connection, but unplugging/replugging the hub restored full USB3 speed. This has only happened once, but I haven't used this particular hub enough to know if it's truly a recurring problem like #1, or was just a one-time fluke.

Don't know about your specific user case but as you can read on the previous page in this thread me and some users experience some issues after updating to Sonoma.

 

[WilliamG]

Hey all, - with the TS4, is it better to plug my bookshelf speakers directly into the 3.5mm on the TS4 rear, or would I get better audio quality using the Apple USB C to 3.5mm plugged into one of the USB C ports on the TS4? Thank you.

 

[phrehdd]

Hey all, - with the TS4, is it better to plug my bookshelf speakers directly into the 3.5mm on the TS4 rear, or would I get better audio quality using the Apple USB C to 3.5mm plugged into one of the USB C ports on the TS4? Thank you.

I would contact Caldigit and ask what type of DAC do they use and run the question by them. My guess is if they respond they will tell you to plug directly into one of the 3.5mm inputs on the TS4.

If your speakers are very good, then consider a not too expensive external DAC (digital to audio converter) that has a 3.5mm imput that can match your speakers' impedance. There is not only the idea of better sound but depending on the DAC, you can play much higher resolution audio files.

 

[WilliamG]

I would contact Caldigit and ask what type of DAC do they use and run the question by them. My guess is if they respond they will tell you to plug directly into one of the 3.5mm inputs on the TS4.

If your speakers are very good, then consider a not too expensive external DAC (digital to audio converter) that has a 3.5mm imput that can match your speakers' impedance. There is not only the idea of better sound but depending on the DAC, you can play much higher resolution audio files.

Thank you. I don’t know if my speakers are that good (Eris 4.5).

 

[phrehdd]

Thank you. I don’t know if my speakers are that good (Eris 4.5).

With those speakers, I would plug the 3.5 directly into the Mac and then try it on the TS4 and decide which sound you like better. I say this as it is not a speaker type that gives a flat frequency response. Skip the USB option.

 

[WilliamG]

With those speakers, I would plug the 3.5 directly into the Mac and then try it on the TS4 and decide which sound you like better. I say this as it is not a speaker type that gives a flat frequency response. Skip the USB option.

Righto. I'm pretty happy with these connected to the TS4, so maybe I'll just leave well enough alone as a tidy, single-cable solution via TB4. Thank you.