Clarify Proxmox LXC instructions; reference #5773 instead of #1111 (#10759)

* Clarify Proxmox LXC instructions

There is a lot of confusing information online. This provides some
simple general guidelines to help people get started.

* Update docs/docs/frigate/installation.md

Co-authored-by: Nicolas Mowen <nickmowen213@gmail.com>

* Reference #5773 instead of #1111

---------

Co-authored-by: Nicolas Mowen <nickmowen213@gmail.com>

docs/docs/frigate/installation.md

@@ -13,7 +13,7 @@ Frigate is a Docker container that can be run on any Docker host including as a
 
 ### Operating System
 
-Frigate runs best with docker installed on bare metal debian-based distributions. For ideal performance, Frigate needs access to underlying hardware for the Coral and GPU devices. Running Frigate in a VM on top of Proxmox, ESXi, Virtualbox, etc. is not recommended. The virtualization layer often introduces a sizable amount of overhead for communication with Coral devices, but [not in all circumstances](https://github.com/blakeblackshear/frigate/discussions/1837).
+Frigate runs best with Docker installed on bare metal Debian-based distributions. For ideal performance, Frigate needs low overhead access to underlying hardware for the Coral and GPU devices. Running Frigate in a VM on top of Proxmox, ESXi, Virtualbox, etc. is not recommended though [some users have had success with Proxmox](#proxmox).
 
 Windows is not officially supported, but some users have had success getting it to run under WSL or Virtualbox. Getting the GPU and/or Coral devices properly passed to Frigate may be difficult or impossible. Search previous discussions or issues for help.
 
@@ -202,7 +202,16 @@ To install make sure you have the [community app plugin here](https://forums.unr
 
 ## Proxmox
 
-It is recommended to run Frigate in LXC for maximum performance. See [this discussion](https://github.com/blakeblackshear/frigate/discussions/1111) for more information.
+It is recommended to run Frigate in LXC, rather than in a VM, for maximum performance. The setup can be complex so be prepared to read the Proxmox and LXC documentation. Suggestions include:
+
+- For Intel-based hardware acceleration, to allow access to the `/dev/dri/renderD128` device with major number 226 and minor number 128, add the following lines to the `/etc/pve/lxc/<id>.conf` LXC configuration:
+  - `lxc.cgroup2.devices.allow: c 226:128 rwm`
+  - `lxc.mount.entry: /dev/dri/renderD128 dev/dri/renderD128 none bind,optional,create=file`
+- The LXC configuration will likely also need `features: fuse=1,nesting=1`. This allows running a Docker container in an LXC container (`nesting`) and prevents duplicated files and wasted storage (`fuse`).
+- Successfully passing hardware devices through multiple levels of containerization (LXC then Docker) can be difficult. Many people make devices like `/dev/dri/renderD128` world-readable in the host or run Frigate in a privileged LXC container.
+- The virtualization layer often introduces a sizable amount of overhead for communication with Coral devices, but [not in all circumstances](https://github.com/blakeblackshear/frigate/discussions/1837).
+
+See the [Proxmox LXC discussion](https://github.com/blakeblackshear/frigate/discussions/5773) for more general information.
 
 ## ESXi