JetPack 4.6.3 preempt-rt patkernel: reboot loop

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
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24

After testing, I am seeing a number of issues with R32.7.4 with the RT patches applied.

  1. If nvpmodel runs at boot, I get a boot hang. If this service fails (which seems to happen more often than not), I am able to boot just fine. I am unable to get the system to hang after a successful boot via re-running nvpmodel. If I disable the service, I am able to boot with 100% success. If I try to change what nvpmodel mode is applied by default (including keeping all cores active), boot still hangs if the service runs.
  2. rt-tests fails in spectacular fashion if I do get a good boot. Namely, sigwaittest -t 4 -f shows latency spikes on the order of several milliseconds (I would expect my worst case performance to be closer to the average, which is a few microseconds). Also, rt-migrate-test -c -p 60 fails repeatedly showing that lower priority tasks are scheduled ahead of high priority tasks. Note that all these tests were run with the Denver cores disabled.
  3. If I increase kernel debug flags in my kernel config, I am able to duplicate @damien.lefevre results, and also see a few additional kernel BUGs. I attempted to apply the fix I found from another post (R32.7.1 / 4.9.253-rt168 : BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:987), which did not resolve any of my issues (including kernel BUGs being reported due to the DEBUG flags being set). In fact, the only thing that seems to resolve my issues is not applying the RT patches, which is unfortunately a requirement for my use case.

@DaveYYY When can we expect the RT patchset to be supported in L4T (again) for the TX2?