Product Documentation

Configure graphics

This article provides guidance for Linux VDA graphics configuration and fine-tuning.

For more information, see System requirements and the Installation overview section.

Configuration

Thinwire is the display remoting technology used in the Linux VDA. The technology allows graphics generated on one machine to be transmitted, typically across a network, to another machine for display.

The Use video codec for compression graphics policy sets the default graphics mode and provides the following options for different use cases:

  • Use when preferred. This setting is the default. No additional configuration is required. Keeping this setting ensures that Thinwire is selected for all Citrix connections, and optimized for scalability, bandwidth, and superior image quality for typical desktop workloads.
  • For the entire screen. Delivers Thinwire with full-screen H.264 or H.265 to optimize for improved user experience and bandwidth, especially in cases with heavy use of 3D graphics.
  • For actively changing regions. The adaptive display technology in Thinwire identifies moving images (video, 3D in motion), and uses H.264 only in the part of the screen where the image is moving.

Some other policy settings, including the following visual display policy settings can be used to fine-tune the performance of display remoting:

By default, the Build to Lossless preference of the Visual quality policy setting is now H.264 instead of JPEG for moving images. For more information, see What’s new.

Starting with the 7.18 release, the Linux VDA supports the H.265 video codec for hardware acceleration of remote graphics and videos. You can use this feature on Citrix Receiver for Windows 4.10 and later. To benefit from this feature, enable it on both the Linux VDA and on Citrix Receiver.

To enable H.265 hardware encoding on the VDA:

  1. Enable the Use hardware encoding for video codec policy.
  2. Enable the Optimize for 3D graphics workload policy
  3. Ensure that the Use video codec for compression policy is default or set to For the entire screen.
  4. Ensure that the Visual quality policy is NOT set to Build to Lossless or Always Lossless.

To enable H.265 hardware encoding on Citrix Receiver for Windows, see H.265 video encoding.

For a full list of the policies supported by the Linux VDA Thinwire, see Policy support list.

For information on the configuration of multi-monitor support on the Linux VDA, see CTX220128.

Troubleshooting

Check which encoding mode is in use

Run the following command to check which encoding mode is in use (0 means TW+; 1 means full-screen H.264; 2 means full-screen H.265):

sudo /opt/Citrix/VDA/bin/ctxreg dump | grep H264

The results resemble:

create -k "HKLM\Software\Citrix\Ica\Session\1\Graphics" -t "REG_DWORD" -v "H264" -d "0x00000001" --force

Check whether hardware encoding is in use for 3D Pro

Run the following command (0 means not in use; 1 means in use):

sudo /opt/Citrix/VDA/bin/ctxreg dump | grep HardwareEncoding

The results resemble:

create -k "HKLM\Software\Citrix\Ica\Session\1\Graphics" -t "REG_DWORD" -v "HardwareEncoding" -d "0x00000001" --force

Another way is to use the nvidia-smi command. The output resembles the following if hardware encoding is in use:

Tue Apr 12 10:42:03 2016
+------------------------------------------------------+
| NVIDIA-SMI 361.28     Driver Version: 361.28         |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GRID K1             Off  | 0000:00:05.0     Off |                  N/A |
| N/A   42C    P0    14W /  31W |    207MiB /  4095MiB |      8%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID  Type  Process name                               Usage      |
|=============================================================================|
|    0      2164  C+G   /usr/local/bin/ctxgfx                          106MiB |
|    0      2187    G   Xorg                                            85MiB |
+-----------------------------------------------------------------------------+

Verify that the NVIDIA GRID graphics driver is installed correctly

To verify that the NVIDIA GRID graphics driver is installed correctly, run nvidia-smi. The results resemble:

+------------------------------------------------------+
| NVIDIA-SMI 352.70     Driver Version: 352.70         |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  Tesla M60           Off  | 0000:00:05.0     Off |                  Off |
| N/A   20C    P0    37W / 150W |     19MiB /  8191MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID  Type  Process name                               Usage      |
|=============================================================================|
|  No running processes found                                                 |
+-----------------------------------------------------------------------------+

Set the correct configuration for the card:

etc/X11/ctx-nvidia.sh

HDX 3D Pro multi-monitor redraw issues

If you are seeing redraw issues on screens other than the primary monitor, check that the NVIDIA GRID license is available.

Check Xorg error logs

The log file of Xorg is named similar to Xorg.{DISPLAY}.log in the /var/log/ folder.

Known issues and limitations

For vGPU, the XenServer local console shows the ICA desktop session screen

Workaround: Disable the VM’s local VGA console by running the following command:

xe vm-param-set uuid=<vm-uuid> platform:vgpu_extra_args="disable_vnc=1"

NVIDIA K2 graphics cards do not support YUV444 hardware encoding in pass-through mode

With Build to Lossless enabled through the policy setting, a black or gray screen appears when users are launching an app/desktop session with an NVIDIA K2 graphics card. The issue occurs because NVIDIA K2 graphics cards do not support YUV444 hardware encoding in pass-through mode. For more information, see Video Encode and Decode GPU Support Matrix.

Gnome 3 desktop popups slow when logging on

It is a limitation of Gnome 3 desktop session startup.

Some OpenGL/WebGL applications do not render well upon resizing the Receiver window

Resizing the Citrix Receiver window changes screen resolution. The NVIDIA proprietary driver changes some internal states and might require applications to respond accordingly. For example, the WebGL library element lightgl.js might spawn an error saying that ‘Rendering to this texture is not supported (incomplete frame buffer)’.

Configure graphics