USB add-in PCIe card passthrough to avoid mouse lag

[ng0177]

Hello,

after successfully adding a USB add-in PCIe card and separating the IOMMU groups, it is added as Hardware "Raw Device" to the VM, see below.

However, the mouse lag experienced, if I access the VM remote through a Browser with noVNC does not disappear. I guess, I am missing something fundamental and grateful for hints.

 

[leesteken]

Does the mouse lag go away when you unplug the keyboard (assuming they are on the same controller)? Maybe try booting with Proxmox kernel version 6.8.8 instead of the current 6.8.12. It could be the same problem I have with a ASM3241.

 

[ng0177]

grub has 6.8.4 but not 6.8.8 on offer, the former makes no change. I still think that I have a conceptual problem: just passing through the controler should not be sufficient but somehow the physical mouse being used in the browser should need to hook to (edit) the Raw Device (I have not checked the All Functions check box)?

 

[leesteken]

I still think that I have a conceptual problem: just passing through the controler should not be sufficient but somehow the physical mouse being used in the browser should need to hook the Raw Device (I have not checked the All Functions check box)?

I don't understand the question, sorry. Your PCI(e) passthrough looks fine and device with PCI ID 21:00 has no multiple functions (there is only 21:00.0 and no 21:00.1, 21:00.2, etc.). I don't have experience with noVNC as I use GPU passthrough or SPICE or serial console with xterm.js. Can you elaborate on your question a bit?

 

[ng0177]

A picture says more than 1000 words (probalby not). The simple question is: how does passthrough prevent the mouse lag in the VMs, if

1. the physical mouse on the laptop is not connected the passed-through device
2. the default noVNC protocal may be the issue in the first place
3. on the forum we have multiple recommendations to passthrough a PCIe/UBS card to deal with it

I think, I am missing something.

 

[leesteken]

The simple question is: how does passthrough prevent the mouse lag in the VMs, if

1. the physical mouse on the laptop is not connected the passed-through device
2. the default noVNC protocal may be the issue in the first place
3. on the forum we have multiple recommendations to passthrough a PCIe/UBS card to deal with it

It's probably not mouse lag but display lag, since you are viewing remotely. The USB lag recommendation is valid when you also do GPU passthrough and are sitting at the Proxmox host.

 

[ng0177]

It's probably not mouse lag but display lag, since you are viewing remotely. The USB lag recommendation is valid when you also do GPU passthrough and are sitting at the Proxmox host.

That is what I gathered. Thanks.

Any recommendations as to how - easiest - avoid the display lag on remote viewing?

 

[leesteken]

Any recommendations as to how - easiest - avoid the display lag on remote viewing?

Maybe try Steam Link or Parsec or NoMachine? There are threads about that on this forum.
Also, it might not even be noVNC since (without GPU passthrough to the VM) the screen/mouse drawing by the CPU (virtual cores inside the VM) might be slow part.

EDIT: Without a GPU, the display compressions (for faster network transfers) might also not work very well (when using other remote viewing software).

 

[ng0177]

The CPU of the host is a AM4 AMD Ryzen 7 1700 that necessitates a graphics board: 4GB Sapphire Radeon RX 550 Pulse Aktiv PCIe 3.0 x16 (x8). I wonder, if the critical path is to start looking GPU passthrough due to that first?