Enable Linux PREEMPT_RT

Author: fhunleth

linux-6.6.defconfig

@@ -4,7 +4,7 @@ CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y
-CONFIG_PREEMPT=y
+CONFIG_PREEMPT_RT=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 CONFIG_MEMCG=y
@@ -14,11 +14,13 @@ CONFIG_CGROUP_PIDS=y
 CONFIG_CGROUP_FREEZER=y
 CONFIG_CGROUP_DEVICE=y
 CONFIG_CGROUP_CPUACCT=y
+CONFIG_NAMESPACES=y
 # CONFIG_UTS_NS is not set
 # CONFIG_IPC_NS is not set
 # CONFIG_PID_NS is not set
 # CONFIG_NET_NS is not set
 CONFIG_SCHED_AUTOGROUP=y
+CONFIG_EXPERT=y
 # CONFIG_PERF_EVENTS is not set
 CONFIG_PROFILING=y
 CONFIG_ARCH_MULTI_V6=y
@@ -41,7 +43,6 @@ CONFIG_ARM_RASPBERRYPI_CPUFREQ=y
 CONFIG_VFP=y
 # CONFIG_SUSPEND is not set
 CONFIG_PM=y
-CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODVERSIONS=y
@@ -146,9 +147,9 @@ CONFIG_SPI_BCM2835AUX=y
 CONFIG_SPI_SPIDEV=y
 # CONFIG_PTP_1588_CLOCK is not set
 CONFIG_GPIO_BCM_VIRT=y
-CONFIG_W1=y
-CONFIG_W1_MASTER_GPIO=y
-CONFIG_W1_SLAVE_THERM=y
+CONFIG_W1=m
+CONFIG_W1_MASTER_GPIO=m
+CONFIG_W1_SLAVE_THERM=m
 CONFIG_POWER_RESET=y
 CONFIG_POWER_RESET_GPIO=y
 CONFIG_POWER_SUPPLY=y
@@ -161,11 +162,15 @@ CONFIG_BCM2835_WDT=y
 CONFIG_BCMA=m
 CONFIG_MFD_RASPBERRYPI_POE_HAT=m
 CONFIG_REGULATOR=y
-CONFIG_REGULATOR_FIXED_VOLTAGE=m
+CONFIG_REGULATOR_FIXED_VOLTAGE=y
 CONFIG_REGULATOR_AD5398=m
+CONFIG_REGULATOR_GPIO=y
+CONFIG_REGULATOR_RASPBERRYPI_TOUCHSCREEN_ATTINY=m
 CONFIG_MEDIA_SUPPORT=m
+CONFIG_MEDIA_SUPPORT_FILTER=y
 CONFIG_MEDIA_CAMERA_SUPPORT=y
 CONFIG_MEDIA_PLATFORM_SUPPORT=y
+CONFIG_V4L_PLATFORM_DRIVERS=y
 CONFIG_VIDEO_BCM2835_UNICAM=m
 CONFIG_VIDEO_RASPBERRYPI_PISP_BE=m
 CONFIG_VIDEO_IMX219=m
@@ -218,7 +223,6 @@ CONFIG_LEDS_TRIGGER_TIMER=y
 CONFIG_LEDS_TRIGGER_ONESHOT=y
 CONFIG_LEDS_TRIGGER_HEARTBEAT=y
 CONFIG_LEDS_TRIGGER_BACKLIGHT=y
-CONFIG_LEDS_TRIGGER_CPU=y
 CONFIG_LEDS_TRIGGER_DEFAULT_ON=y
 CONFIG_LEDS_TRIGGER_TRANSIENT=y
 CONFIG_LEDS_TRIGGER_INPUT=y
@@ -270,3 +274,4 @@ CONFIG_DMA_CMA=y
 CONFIG_CMA_SIZE_MBYTES=5
 CONFIG_PRINTK_TIME=y
 CONFIG_PANIC_TIMEOUT=10
+# CONFIG_FTRACE is not set

nerves_defconfig

@@ -29,7 +29,7 @@ BR2_ROOTFS_POST_IMAGE_SCRIPT="${NERVES_DEFCONFIG_DIR}/post-createfs.sh"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_TARBALL=y
 BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="https://github.com/raspberrypi/linux/archive/refs/tags/stable_20241008.tar.gz"
-BR2_LINUX_KERNEL_PATCH="${NERVES_DEFCONFIG_DIR}/linux"
+BR2_LINUX_KERNEL_PATCH="http://cdn.kernel.org/pub/linux/kernel/projects/rt/6.6/patch-6.6.53-rt44.patch.gz ${NERVES_DEFCONFIG_DIR}/linux"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="${NERVES_DEFCONFIG_DIR}/linux-6.6.defconfig"
 BR2_LINUX_KERNEL_XZ=y