Raspberry Pi 4 release notes

1.0

Realtime kernel Raspberry 4.19.71-1-rt24-ARCH


Very good CPU latency with a variation in test of only 5us max, 2us avg!

[root@raspberry audiolinux]# cyclictest  -l 10000 -m -Sp98 -i100 -d0
# /dev/cpu_dma_latency set to 0us
policy: fifo: loadavg: 3.72 1.93 0.76 1/166 15651         

T: 0 (15648) P:98 I:100 C:  10000 Min:      4 Act:    4 Avg:    4 Max:      14
T: 1 (15649) P:98 I:100 C:   9725 Min:      4 Act:    6 Avg:    4 Max:      10
T: 2 (15650) P:98 I:100 C:   9463 Min:      4 Act:    4 Avg:    4 Max:       9
T: 3 (15651) P:98 I:100 C:   9150 Min:      4 Act:    5 Avg:    4 Max:      10

Ramroot possible with 4GB model

MAIN MENU

         0 "PROFILES menu"
         1 "AUDIO menu"
         2 "SYSTEM menu"
         3 "STATUS menu"
         4 "INSTALL/UPDATE menu"
         5 "EXPERT menu"
         6 "Show configuration"
         7 "Console mode"
         8 "SAVE System (if in ram mode)"
         9 "Poweroff"
         10 "Reboot"

SYSTEM MENU

         1 "FILE EDITOR"
         2 "FILE EDITOR root"
         3 "MOUNT local drive"
         4 "MOUNT remote drive"     
         5 "CLEAN system"
         6 "RESIZE AL partition (if in ram mode)"
         7 "FORMAT extra drive"
         8 "NETWORK configuration (Bridge, DHCP, Static IP)"
         9 "WiFi"
         10 "REALTIME PRIORITY to standard or extreme"      
         11 "RAMROOT enable/disable (reboot after)"
         12 "RAMROOT configuration"
         13 "BOOT mode to Extreme, Standard or Custom"
         14 "OVERLAYS configuration"
         15 "CPU SPEED to performance or ondemand"
         16 "ISOLATED CPU CORES configuration"
         17 "SAVE System (if in ram mode)"

AUDIO MENU

         1 "SHOW audio services"
         2 "STOP and disable all running audio services"
         3 "HQPLAYER start and enable (not available)"
         4 "ROONSERVER start and enable (not available)"
         5 "ROONBRIDGE start and enable"
         6 "NAA start and enable"
         7 "AIRPLAY start and enable"
         8 "SQUEEZELITE select DAC"
         9 "SQUEEZELITE start and enable"
         10 "LMS start and enable"
         11 "MPD select DAC, music directory and buffer"
         12 "MPD start and enable"
         13 "MPD UPnP start and enable"
         14 "SPOTIFY start and enable"
         15 "SAVE System (if in ram mode)"

UPDATE MENU

         1 "Install/Update Roonbridge"
         2 "Install/Update HQPlayer embedded (not available)"
         3 "Install/Update NAA"
         4 "Update kernel (for expert users)"
         5 "System update (for expert users)"
         6 "Update audiolinux menu"
         7 "Install/Update MPD"
         8 "Install/Update UPnP for MPD"
         9 "Install/Update Logitech Media Server"
         10 "Install/Update Squeezelite"
         11 "Install/Update Spotify"
         12 "Install/Update Shairport-sync"
         13 "Remove installed audio applications"
         14 "SAVE System (if in ram mode)"

EXPERT MENU

         1 "Assign a specific isolated core to audio applications"
         2 "REALTIME EXPERT CONFIGURATION enable/disable"
         3 "REALTIME MANUAL ASSIGNMENT enable/disable"
         4 "ETHERNET speed limit"
         5 "WEB INTERFACE enable/disable"
         6 "ALSA system wide configuration"
         7 "SAMBA SERVER enable/disable"
         8 "SAMBA SERVER add share"
         9 "ENABLE/DISABLE bluetooth"
         10 "ENABLE/DISABLE WiFi"
         11 "SAVE System (if in ram mode)"

PROFILES MENU

         1 "Green"
         2 "Orange (default)"
         3 "Red"
         4 "Auto (generated by menus)"
         5 "Copy Auto to Custom"
         6 "Custom1"
         7 "Custom2"
         8 "Custom3"

Example configuration:

RTMANUAL="1"   
RTEXPERT="0"
PRIORITY="standard"
CPUSPEED=""
BOOT="extreme"
ISOLATED="0"
ISOLATEDIRQ="0"
SAMBA=""

# RTMANUAL: realtime manual assignment        "1" enabled, "0" disabled
# RTEXPERT: realtime expert configuration     "1" enabled, "0" disabled
# PRIORITY: realtime priority             "standard", "extreme"
# CPUSPEED: CPU frequency             "performance", "ondemand" not available in realtime kernel
# BOOT: boot mode                   "standard", "extreme", "custom"
# If you have configured boot mode with "SET CPU C-states" in Expert menu, set this to an empty value
# ISOLATED: isolate a set of cores               "0" disabled, <core number> (first is 0, not available) or an interval of cores
# For example 1-2 will isolate core 1,2 / 1-3 wil isolate core 1,2,3 / 2 will isolate only core 2
# If enabled, all audio services will be disabled and hyper-threading disabled even if set to 1 (enabled) on this configuration file
# You can re-enable your audio services after reboot
# ISOLATEDIRQ: isolate audio irqs                "1" enabled, "0" disabled
# This will disable C-state configuration in expert menu
# SAMBA: samba server                 "1" enabled, "0" disabled

# IMPORTANT: if value is empty your configuration will not be changed.
# This is useful if you have applied some special configuration, for example if you have activated C-state in expert menu
# Example: BOOT=""

---------------

For Allo DigiOne, you should add the line
dtoverlay=allo-digione
to /boot/config.txt

For Metrum Ambre, you should add the line
dtoverlay=hifiberry-digi-pro

to /boot/config.txt

For Allo boss, you should add the line
dtoverlay=allo-boss-pcm512x-audio

to /boot/config.txt

For I2S DAC (this configuration was tested on a rpi3/Sllo isolator/Kali reclocker/Soekris 1121 DAC)
dtparam=i2c_arm=on
dtparam=i2s=on
dtparam=audio=off
dtoverlay=rpi-dac

For a full list of Raspberry options: https://www.raspberrypi.org/documentation/configuration/config-txt/overclocking.md