*Linux* Output range (Broadcast RGB) on Displayport Automatic sets to Limted

[Forester]

Hi.

I'm using Intel GPU on Linux and Windows with both an 8th Gen NUC (Iris Plus 655) and an i5-3470S on an Intel DH77DF motherboard (...Intel all the way? 🙂 )

Windows detects the correct output range on several monitors (Dell P2314H, Iiyama XUB2493HSU-B1 and Dell U2419H) correctly and outputs Full range/Full RGB.

Linux however seems to default to Limited 16:235 on both the NUC and DH77DF system and with all 3 monitors.

Using xorg you can have a startup script to use xrandr to force Broadcast RGB to Full but on Wayland/Gnome there's no easy way to do this.

System is running Fedora 33 and 5.9.8 Kernel (latest Fedora Kernel available)

I've also tried a live boot USB with both Gnome/wayland and KDE/xorg with the same results on both the NUC and DH77DF.

Any ideas? I don't think this is what the default behavious should be for Automatic Broadcast RGB via Displayport 🙂

Thanks for any help you can provide.

[AndrewG_Intel]

Hello @Forester

Thank you for posting on the Intel® communities.

It is worth mentioning that we usually support one issue per thread and per product. Due to this fact and also since the Intel® Desktop Board DH77DF, Intel® Core™ i5-3470S Processor and its graphics Intel® HD Graphics 2500 have been discontinued (all of them), Intel Customer Service no longer supports inquiries for them.

Perhaps fellow community members have the knowledge to help so we recommend creating a separate thread for peer-to-peer support. You may also find the Discontinued Products website helpful to address your request:

https://www.intel.com/content/www/us/en/support/discontinued-products.html

Having said that, we will focus on the Intel® NUC. Not all Intel® NUCs have been validated and tested to work with Linux operating systems. You can find the list of validated NUCs for Linux in the following link:

• https://www.intel.com/content/www/us/en/support/articles/000005499/intel-nuc.html

Intel® NUCs not included in the previous website as tested or validated with Linux may work or may not work properly.

Since the Intel® NUC works fine under Windows*, this could be an issue related to the Linux operating system (OS). We recommend checking this further with the Linux OS vendor or their forum* (e.g: https://www.fedoraforum.org/), install the latest kernel, and use their distribution resources for driver downloads and support.

However, in order to take a look into this behavior, could you please provide the following information from your NUC:

1- Exact Intel® NUC model. You may check on the label on the bottom of the chassis. Refer to "Product Code" and "Regulatory Model".

2- Intel® System Support Utility for the Linux* Operating System >> https://downloadcenter.intel.com/download/26735/Intel-System-Support-Utility-for-the-Linux-Operating-System

3- Log >> /var/log/dmesg (You can also view the content of this file using the $ dmesg -c)

4- Log >> /var/log/kern.log

5- Are you using a straight-through connection (DisplayPort*-to-DisplayPort) with a single cable?

Best regards,

Andrew G.

Intel Customer Support Technician

*Links to third-party sites and references to third-party trademarks are provided for convenience and illustrative purposes only. Unless explicitly stated, Intel® is not responsible for the contents of such links, and no third-party endorsement of Intel® or any of its products is implied.

[Forester]

Hi, thanks for your reply and apologies for the delay in mine 🙂

The NUC is a NUC8i5BEH.

Sadly it  hasn't been validated for use on Linux...but then only NUC7's seem to have been...and on Ubuntu/libreelec/clear only...

So moving on 🙂

The cable I'm using is a USB-C to Displayport cable. It's the same behaviour when using a generic "8K capable" cable or an AmazonBasics uni-directional cable. (NUC8i5BEH only has HDMI or alt-mode DP from USB-C for outputs. I'm also not using Thunderbolt.)

Please find the requested files. I ran SSU on KDE (xorg) and Gnome (wayland) but I can't see much in there different.

Thanks

[AndrewG_Intel]

Hello Forester

We are checking this thread and we would like to know if you need further assistance. Please do not hesitate to contact us back if you have additional inquiries.

Best regards,

Andrew G.

Intel Customer Support Technician

[AndrewG_Intel]

Hello Forester

Thank you very much for the information. Please allow us to take a look into this and we will be updating this thread as soon as we have more details.

Best regards,

Andrew G.

Intel Customer Support Technician

[Ronny_G_Intel]

Hi Forester,

I have been looking into this report along with Andrew but unfortunately, we offer very limited Linux* support for NUC models that hasn't been validated with, I think that you are aware of that already. Here is our Supported Operating Systems List for Intel® NUC Products.

In addition to that, we don't provide drivers for Linux as most Linux-based* distributions include Intel® Graphics Drivers and these drivers are provided and maintained by the Linux* distribution vendors not by Intel so we don't really know what features are supported by these drivers 

I would recommend that you contact your operating system vendor for further support on this issue.

One more resource that you can try is https://01.org/linuxgraphics however the latest recipe available is from 2018.

Regrads,

Ronny G

[AndrewG_Intel]

Hello @Forester

We have not heard back from you so we will proceed to close this thread now. If you need any additional information, please submit a new question as this thread will no longer be monitored.

Best regards,

Andrew G.

Intel Customer Support Technician