Arch Linux

chippey5

Member

From: Sweden

Registered: 2015-10-26

Posts: 8

x0vncserver extremely slow on LAN without a connected monitor

I have a server set up with an x0vncserver (TigerVNC) on it. When I first tested the connection to it from another computer on the same network, having a monitor connected to the server, the connection was smooth and fast. But as soon as I disconnected the monitor from the server, the resolution shrinked to VGA quality and I got about 1 frame/second when connecting to it. Below is the code I use in systemd for it, and yet it does not give the declared resolution and gives me an extremely slow refresh rate.

x0vncserver -display :0 -geometry 1920x1080 -rfbport 5900 -passwordfile /my/path/to/password/passwd

Any ideas? The biggest thing that bugs me is the slowness of the connection, even though the server and client are on LAN.

Last edited by chippey5 (2018-04-14 15:15:20)

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,719

Website

Re: x0vncserver extremely slow on LAN without a connected monitor

Is it different if you omit the -geometry switch?

---

AUR packages • Zsh and other configs

chippey5

Member

From: Sweden

Registered: 2015-10-26

Posts: 8

Re: x0vncserver extremely slow on LAN without a connected monitor

Nope, same issue when excluding the geometry switch. I get the following from the x0vncserver console upon connection (I'm not sure if it's useful but here it is):

 EncodeManager: Framebuffer updates: 15
 EncodeManager:   RRE:
 EncodeManager:     Solid: 3 rects, 180.224 kpixels
 EncodeManager:            54 B (1:6979.04 ratio)
 EncodeManager:   Hextile:
 EncodeManager:     Indexed RLE: 2 rects, 131.072 kpixels
 EncodeManager:                  9.73926 KiB (1:52.5731 ratio)
 EncodeManager:     Full Colour: 12 rects, 610.304 kpixels
 EncodeManager:                  198.504 KiB (1:12.0105 ratio)
 EncodeManager:   ZRLE:
 EncodeManager:     Bitmap RLE: 6 rects, 245.76 kpixels
 EncodeManager:                 411 B (1:598.131 ratio)
 EncodeManager:     Indexed RLE: 31 rects, 1.40493 Mpixels
 EncodeManager:                  29.8574 KiB (1:45.9639 ratio)
 EncodeManager:   Total: 54 rects, 2.57229 Mpixels
 EncodeManager:          238.555 KiB (1:20.4424 ratio)
 ComparingUpdateTracker: 12.5829 Mpixels in / 999.424 kpixels out
 ComparingUpdateTracker: (1:12.5902 ratio)

chippey5

Member

From: Sweden

Registered: 2015-10-26

Posts: 8

Re: x0vncserver extremely slow on LAN without a connected monitor

Okay, so I connected a monitor again, then connected to the vncserver and I get a steady and smooth refresh rate. Disconnecting the display makes it stay the same until I reboot the server, then the issue appears again.

chippey5

Member

From: Sweden

Registered: 2015-10-26

Posts: 8

Re: x0vncserver extremely slow on LAN without a connected monitor

Upon a lot of Googling and tweaking, the root cause seems to be with Xorg not being started as long as no monitor is connected, hence the "slowness", making it fall back to the slow refresh rate.

I have tried creating different virtual monitors under /etc/X11/xorg.conf.d/10-monitor.conf, only resulting in the lightdm service to fail. I have also tried this by installing xf86-video-dummy without any luck. I just can't seem to get around this issue.

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,719

Website

Re: x0vncserver extremely slow on LAN without a connected monitor

Can you use vncserver virtually or does it have to be the physical, disconnected, monitor?

---

AUR packages • Zsh and other configs

chippey5

Member

From: Sweden

Registered: 2015-10-26

Posts: 8

Re: x0vncserver extremely slow on LAN without a connected monitor

The goal is to use TigerVNC, so that I can connect and use my Server without a connected monitor. I currently run LightDM as display manager and Cinnamon as Desktop Environment. Note that I use x0vncserver (from TigerVNC) and not vncserver, quote: "tigervnc provides the x0vncserver binary which allows direct control over a physical X session." (TigerVNC Arch Wiki). I want VNC to take over the ongoing (physical) session on the server.

Headless mode works (using vncserver -args), but I prefer having it connected to the running X session. Additionally, when running it in headless mode, Cinnamon drops into fallback mode (software rendering), but that's another issue for another topic.

I will most probably buy a dummy HDMI to circumvent this, as most people seem to do this in headless mode to connect to their headless servers.

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,719

Website

Re: x0vncserver extremely slow on LAN without a connected monitor

OK... I understand you use case.

---

AUR packages • Zsh and other configs