# udev rules specific to RHEL-RT Realtime kernel
 
# insure /dev/rtc points to /dev/rtc0
# we use PROGRAM rather than SYMLINK because there is
# a (good) possibility that a /dev/rtc device file
# already exists and we want to replace it (hence the
# ln -sf)
KERNEL=="rtc0", PROGRAM+="/bin/ln -sf rtc0 /dev/rtc"
 
# Give permission to the realtime group to write a zero to /dev/cpu_dma_latency
# This will tell the power management system not to transition to a high cstate
KERNEL=="cpu_dma_latency", GROUP="realtime"
 
# Give permission to the realtime group to read the per cpu msr and cpuid
# registers. This is needed by cyclictest in rt-tests when using the new
# feature to read the smi counters. This is necessary but not sufficient
# A program that wants to access these registers will also need CAP_SYS_RAWIO
SUBSYSTEM=="msr", GROUP="realtime", MODE="0640"
SUBSYSTEM=="cpuid", GROUP="realtime", MODE="0640"