realtime: take advantage of gamescope supporting rt scheduling

build-image.sh

@@ -133,7 +133,7 @@ passwd --lock root
 
 # create user
 groupadd -r autologin
-useradd -m ${USERNAME} -G autologin,wheel,plugdev
+useradd -m ${USERNAME} -G autologin,wheel,plugdev,realtime,audio,video
 echo "${USERNAME}:${USERNAME}" | chpasswd
 
 # set the default editor, so visudo works

manifest

@@ -212,7 +212,6 @@ export AUR_PACKAGES="\
 	hhfc-git \
 	inputplumber-bin \
 	legendary \
-	lib32-gamescope-plus \
 	libretro-dosbox-pure-git \
 	libretro-opera-git \
 	libretro-prosystem-git \
@@ -227,6 +226,8 @@ export AUR_PACKAGES="\
 	powerstation-bin \
 	python-gbopyrator \
 	python-vdf \
+	realtime-privileges \
+	rtkit \
 	rtl8812au-dkms-git \
 	rtl8814au-dkms-git \
 	rtl88x2bu-dkms-git \
@@ -283,6 +284,9 @@ postinstallhook() {
 	${USERNAME} ALL=(ALL) NOPASSWD: /usr/share/chimera/bin/power-tool
 	" >/etc/sudoers.d/chimera
 
+	# Add chrt permission
+	echo "${USERNAME} ALL=(ALL) NOPASSWD: /usr/bin/chrt" > /etc/sudoers.d/realtime
+
 	# download and add racing wheel udev rules
 	pushd /usr/lib/udev/rules.d
 	curl -L -O https://raw.githubusercontent.com/berarma/oversteer/master/data/udev/99-fanatec-wheel-perms.rules

rootfs/etc/security/limits.d/audio.conf

@@ -0,0 +1,3 @@
+@audio   -  rtprio     99 # maximum realtime priority
+@audio   -  memlock    unlimited # maximum locked-in-memory address space (KB)
+#@audio   -  nice      -19

rootfs/etc/security/limits.d/gamer.conf

@@ -0,0 +1,4 @@
+gamer   soft    memlock	64
+gamer   hard    memlock	128
+gamer   -       rtprio     99 # maximum realtime priority
+gamer   -       memlock    unlimited # maximum locked-in-memory address space (KB)

rootfs/etc/security/limits.d/memlock.conf

@@ -0,0 +1,2 @@
+* hard memlock 2147484
+* soft memlock 2147484

rootfs/etc/security/limits.d/realtime.conf

@@ -0,0 +1,3 @@
+@realtime   -  rtprio     99 # maximum realtime priority
+@realtime   -  memlock    unlimited # maximum locked-in-memory address space (KB)
+#@realtime   -  nice      -19

rootfs/etc/systemd/system/rtkit-daemon.service.d/override.conf

@@ -0,0 +1,6 @@
+# Due to a bug from 2011 (https://github.com/heftig/rtkit/issues/13) in rtkit, suspend events cause PipeWire's realtime priority to be revoked and not restored.
+# Basically priority gets revoked after s2idle or s3 sleep without this. Bug is ongoing.
+
+[Service]
+ExecStart=
+ExecStart=/usr/lib/rtkit-daemon --no-canary

rootfs/etc/udev/rules.d/99-cpu-dma-latency.rules

@@ -0,0 +1 @@
+DEVPATH=="/devices/virtual/misc/cpu_dma_latency", OWNER="root", GROUP="audio", MODE="0660"

rootfs/usr/share/wireplumber/wireplumber.conf.d/realtime.conf

@@ -0,0 +1,16 @@
+context.modules = [
+{   name = libpipewire-module-rt
+    args = {
+        nice.level   = 20
+        rt.prio      = 88
+        rt.time.soft = -1
+        rt.time.hard = -1
+        rlimits.enabled = true
+        rtportal.enabled = true
+        rtkit.enabled = true
+        #uclamp.min = 0
+        #uclamp.max = 1024
+    }
+    flags = [ ifexists nofail ]
+}
+]