# Diretta Synchro Sync Host Install Instructions

## Prerequisites
* Ubuntu Desktop/Server 22.04 LTS or 24.04 LTS
* Install the following packages using apt:
  ```bash
  $ sudo apt install alsa-utils build-essential dkms
  ```

## Download and unzip Diretta Host driver package
* Download ALSA driver version 0.142.12 from [Diretta Preview](https://www.diretta.link/preview/)
* Unzip the drivers using the following command:
  ```bash
  $ tar -xvf DirettaSalsaHost_0_142_12.tar.xz
  ```

## Setup DKMS
* `cd DirettaALSAdriver/`
* Test for build issues with your kernel by running:
  ```bash
  $ make KERNELDIR=/lib/modules/$(uname -r)/build
  ```
> [!NOTE]
> If you're on a kernel older than 6.4.0, you'll likely run across 2 build issues that can be fixed by uncommenting (removing the `//`) from the lines in `alsa_bridge.c` that look like:
> ```c
> #if LINUX_VERSION_CODE < KERNEL_VERSION(6,3,0)
>    vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
> #else
>    vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP);
> #endif
> ```
> and
> ```c
> #if LINUX_VERSION_CODE < KERNEL_VERSION(6, 4, 0)
>     diretta_alsa.class = class_create(THIS_MODULE, "diretta-alsa");
> #else
>     diretta_alsa.class = class_create("diretta-alsa");
> #endif
> ```
* Clean up test build using:
  ```bash
  $ make clean
  ```
* Run `touch dkms.conf` and add the following content:
  ```ini
  MAKE="'make' KERNELDIR=/lib/modules/${kernelver}/build"
  CLEAN="'make' clean"
  BUILT_MODULE_NAME=alsa_bridge
  BUILT_MODULE_LOCATION=./
  DEST_MODULE_LOCATION=/kernel/drivers/alsa/
  PACKAGE_NAME=alsa_bridge
  PACKAGE_VERSION=0.142.12
  REMAKE_INITRD=yes
  AUTOINSTALL=yes
  ```

* Copy the directory into `/usr/src` for DKMS to find it
  ```bash
  $ sudo cp -R . /usr/src/alsa_bridge-0.142.12
  ```

* Run the following commands to enable DKMS for the module:
  ```bash
  $ sudo dkms add -m alsa_bridge -v 0.142.12
  $ sudo dkms build -m alsa_bridge -v 0.142.12
  $ sudo dkms install -m alsa_bridge -v 0.142.12
  ```

* Load the `alsa_bridge` module:
  ```bash
  $ sudo modprobe alsa_bridge
  ```
* Add `alsa_bridge` to `/etc/modules` so the module will load on boot
  ```bash
  $ echo "alsa_bridge" | sudo tee -a /etc/modules
  ```

## Diretta Host Service setup
> [!NOTE]
> If upgrading from the old `diretta_bridge_host`, first disable it by running the following:
> ```bash
> $ sudo systemctl stop diretta_bridge_host
> $ sudo systemctl disable diretta_bridge_host
* Check your version of `gcc` using the following command:
  ```bash 
  $ gcc --version
  ```
> [!NOTE]
> Default `gcc` version for 24.04 is version 13, adjust accordingly for your install
* Edit `/usr/src/alsa_bridge-0.142.12/diretta_ssync_host.service` to the following:
  ```ini
  [Unit]
  Description = Diretta Synchro Alsa Host
  After=network-online.target
  ConditionPathExists=/usr/src/alsa_bridge-0.142.12
  
  [Service]
  ExecStart=/usr/src/alsa_bridge-0.142.12/ssyncAlsa_gcc13_x64_v1
  Restart=always
  Type=simple
  
  [Install]
  WantedBy=multi-user.target
  ```
* Mark the selected service as executable
  ```bash
  $ sudo chmod +x /usr/src/alsa_bridge-0.142.12/ssyncAlsa_gcc13_x64_v1
  ```

* Run the following steps to run `ssyncAlsa` on boot
  ```bash
  $ sudo ln -s /usr/src/alsa_bridge-0.142.12/diretta_ssync_host.service /etc/systemd/system/
  $ sudo systemctl enable diretta_ssync_host
  $ sudo systemctl start diretta_ssync_host
  ```

* To check if ALSA drivers are working correctly, make sure an audio device is connected to the target and run:
  ```bash
  $ sudo aplay -l
  ```

> [!TIP]
> If you want to edit your `settings.inf` to unlock additional performance, try the following settings:
> ```ini
> Interface=
> TargetProfileLimitTime=200
> ThredMode=2
> InfoCycle=100000
> FlexCycle=disable
> CycleTime=800
> CycleMinTime=10
> Debug=disable
> periodMax=32
> periodMin=12
> periodSizeMax=38400
> periodSizeMin=960
> syncBufferCount=8
> alsaUnderrun=enable
> CpuSend=
> CpuOther=
> ```