linux: enable PREEMPT_RT

This includes the real-time patch set and enables 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
@@ -15,11 +15,8 @@ CONFIG_CGROUP_FREEZER=y
 CONFIG_CPUSETS=y
 CONFIG_CGROUP_DEVICE=y
 CONFIG_CGROUP_CPUACCT=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_BCM=y
@@ -44,7 +41,6 @@ CONFIG_NEON=y
 CONFIG_KERNEL_MODE_NEON=y
 # CONFIG_SUSPEND is not set
 CONFIG_PM=y
-CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODVERSIONS=y
@@ -203,7 +199,6 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
 CONFIG_HW_RANDOM=y
 CONFIG_I2C=y
 CONFIG_I2C_CHARDEV=y
-CONFIG_I2C_MUX_PINCTRL=m
 CONFIG_I2C_BCM2708=y
 CONFIG_I2C_BCM2835=y
 CONFIG_SPI=y
@@ -228,8 +223,6 @@ CONFIG_REGULATOR=y
 CONFIG_REGULATOR_FIXED_VOLTAGE=m
 CONFIG_REGULATOR_AD5398=m
 CONFIG_MEDIA_SUPPORT=m
-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
@@ -265,19 +258,8 @@ CONFIG_SND_BCM2708_SOC_GOOGLEVOICEHAT_SOUNDCARD=m
 CONFIG_SND_BCM2708_SOC_HIFIBERRY_DAC=m
 CONFIG_SND_SIMPLE_CARD=m
 CONFIG_HIDRAW=y
-# CONFIG_HID_A4TECH is not set
 CONFIG_HID_APPLE=m
-# CONFIG_HID_BELKIN is not set
-# CONFIG_HID_CHERRY is not set
-# CONFIG_HID_CHICONY is not set
-# CONFIG_HID_CYPRESS is not set
-# CONFIG_HID_EZKEY is not set
-# CONFIG_HID_ITE is not set
-# CONFIG_HID_KENSINGTON is not set
-# CONFIG_HID_LOGITECH is not set
-# CONFIG_HID_REDRAGON is not set
 CONFIG_HID_MICROSOFT=m
-# CONFIG_HID_MONTEREY is not set
 CONFIG_HID_PID=y
 CONFIG_USB_HIDDEV=y
 CONFIG_USB=y
@@ -307,7 +289,6 @@ 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

nerves_defconfig

@@ -30,7 +30,7 @@ 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