USB-C to HDMI dock - no video controls or LUT support
 

I bought a USB-C dock with DisplayPort and HDMI ports. It uses DisplayLink. After I installed the driver, video (color) quality looks bad. Near-white levels clipped to white and near-black levels are crushed to black. My Intel Graphics control panel has gone missing, and the DisplayLink driver appears to have no controls. So I have no way, apparently, to do even basic video settings like brightness, contrast and gamma.

I have color calibration hardware and software. I attempted to use it for this issue but it errored out: "Failed to apply video LUTs" (look up tables).

It appears that I have no way to have a correctly calibrated display, or even a usable one. Yet when I connect the monitor directly to the computer USB-C port with a USB-C-to-HDMI cable, everything works. Please tell me that I have missed something.

Thanks,
Phil

Hello Phil,

I believe there are a few confusions or at least shortcuts in here.
As standard, the driver does zero correction. So if your external display is not setup properly like for instance contrast and brightness pushed, then it will look bad. Claiming the monitor is not "even usable" suggests this is way off.

Brightness and contrast are implemented via a standard called DDC/CI. This standard is implemented through numerous applications like Screenbright. This does not, and never has, required Gamma LUT. Other applications varies based on dock and monitor model as some manufacturers may enable only their hardware.
Should you not wish to use another software, then your monitor should have buttons to at least change brightness and contrast.

Colour calibration through gamma LUT is not publicly released today as the feature is not ready. This is in development in Windows 10, as Windows 7 is end of lifed by Microsoft. Depending on the hardware you have, this might be possible today for you with a registry key as a preview.

Kind regards,
Alban

Thank you Alban. I must admit I had not heard of DDC/CI before this. I did some Googling and learned a bit about it. I think my monitor (LG 32UD59-B) is close to its default settings, but perhaps I can fix the black crush and white clip issues by changing monitor settings.

Even if I'm successful with black and white levels, I don't think I will be able to calibrate gray scale (gamma) and colorimetry properly from there. I'm not sure, but I don't think my calibration gear (x-rite i1Display Pro) can do it without LUT support.

I'm out of the office currently, but will get back to this when I return.

I found a recent review of that monitor taking about picture quality
https://www.rtings.com/monitor/reviews/lg/32ud59-b

DDC/CI won't change gamma.
The display would have settings to change the colour profile and colours individually. At least, the LG display I use at home has.
You're correct that your display calibration hardware will try and send gama correction tables.

The DisplayLink driver released doesn't change gamma tables, so if the image is despicable, it's difficult to blame the thing that doesn't change it...

Depending on the hardware you use, a registry charge might allow you to calibrate your display. As the feature is not ready and only working on specific hardware, it isn't released.
What is the hardware brand and model you have with DisplayLink technology inside? If you've got the Hardware ID from Device Manager advanced details, it also tell me what is inside.

Kind regards,
Alban

I read that review before deciding to buy this monitor. My favorite sentence is "With only minor corrections to the settings, the monitor achieves near-perfect color results." The results the review refers to are after calibration, though.

I tested my DisplayLink device again, this time resetting the monitor to its defaults. Now, black and white levels are spot on - no clipping or crushing. But my x-rite device cannot complete its calibration because it cannot save the LUT it created.

My device that uses DisplayLink technology is WavLink WL-UG69DK1 Rev B.
Device Manager properties, Details tab, Hardware IDs property, says
USB\VID_17E9&PID_6000&REV_0106&MI_00
USB\VID_17E9&PID_6000&MI_00

I hope I have hardware that will allow me to calibrate my monitor. I can make whatever registry changes you suggest.

Hello Phil,

I don't have a build for you today.
Provided it passes the quality bar, this is planned to be a 9.0 deliverable. It won't fit in 8.6 because the feature hasn't been tested yet.

On that product, you will need to use DisplayPort output for LUT support.
I will post when I have something I can share. 9.0 is planned for later this year, after 8.6.

Kind regards,
Alban

Ref 24713, 24647

Thank you Alban. Glad to hear that LUT support is coming. It won't be a problem for me to use DisplayPort instead of HDMI.

Hello,

A colour space mismatch (number of levels) would be the only normal reasons for this.

Otherwise it could be a bug.
The product design doesn't change colours: this isn't something I expect as a normal behaviour.

Kind regards,
Alban

[I don't understand your last post dated 12-01-2018. I suspect it was meant for another thread.]

But back to the LUT support deliverable planned for 9.0. I see that 9.0 M0 is released. Did LUT support make it into this release?

Thanks,
Phil

Hello Phil,

It was referring to black/white levels. This may not be a LUT related thing.
LUT has been implemented but not enabled by default because of some issues on some specific pixel clock ranges (and most people don’t have a clue what ‘pixel clock’ means or how to get it). If you have some missing grey scales, I think this maybe a bug we’ve since identified. The fix isn’t released yet, but we could get you a development build to make sure it fixes it for you as well, unless it’s LUT related.

Here’s how to enable LUT for calibration: https://support.displaylink.com/know...on-displaylink

Kind regards,
Alban

Alban,

I just completed the calibration of my monitor successfully. I am very grateful for the excellent tech support and DisplayLink's willingness to add LUT support so I and others can calibrate our monitors.

Sincerely,
Phil

I lucked into this thread while troubleshooting my x-rite color calibration errors. This solved the problem. I appreciate the excellent support you guys provide.

Hello Alban,

I now would like to calibrate the monitor at another workstation.

It has the same DisplayLink device as mine:
WavLink WL-UG69DK1 Rev B.
Device Manager properties, Details tab, Hardware IDs property, says
USB\VID_17E9&PID_6000&REV_0106&MI_00
USB\VID_17E9&PID_6000&MI_00

The monitor at this workstation does not have a DisplayPort input, so I will be unable to make a DisplayPort-to-DisplayPort connection.

Has anything changed in the last two years that would allow me to color calibrate this monitor using an HDMI connection?

Sincerely,
Phil

Hello Phil,

I'm afraid nothing has changed. No further work is currently planned on this.

The possibility you have is to purchase an ***active*** DisplayPort to HDMI converter.
I insist on the active. A passive converter is just HDMI signal over a DisplayPort plug (DisplayPort++) so will behave as an HDMI.

Generally speaking, passive converters are limited to 4Kp30, so if you look for active DisplayPort to HDMI converter and it shows 4Kp60, it should do the trick.
If you have a preferred vendor, or a product you're thinking of purchasing and want to double check before you buy, you can share a link and I will look.

Kind regards,
Alban