[FS#3099] ipq806x: kernel 5.4 crash related to CPU frequency scaling

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FS#3099 - ipq806x: kernel 5.4 crash related to CPU frequency scaling
User who did this - Shane (digitalcircuit)

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Two new panics/reboots captured on serial console, two new unique logs...

I'm wondering if I might be running into a collection of unrelated bugs with the same trigger (periodic CPU/USB/network usage), or if these bugs are merely symptom of another cause, whether or not it's from the CPU governor changes or something else between 19.07 (good asides from existing ath10k WiFi driver crash), 21.02 (bad), and snapshot (good).

If this is useful, I'll continue collecting data about each reboot.  If this is not useful, or I should be testing or trying something else instead, providing more information, etc, let me know!

See my previous comments (updated) for [[https://bugs.openwrt.org/index.php?do=details&task_id=3099#comment9712|ongoing test results]] and [[https://bugs.openwrt.org/index.php?do=details&task_id=3099#comment9729|hardware serial console setup]].

====Hardware serial console logs====

For the first, it seems like a potential ath10k WiFi driver failure - this one time might be unrelated:


[   58.937876] ath10k_pci 0000:01:00.0: Invalid peer id 1 or peer stats buffer, peer: cd1d2e61  sta: 00000000
[26066.031472] ath10k_pci 0000:01:00.0: htt tx: fixing invalid VHT TX rate code 0xff
[89662.334382] ath10k_pci 0001:01:00.0: wmi: fixing invalid VHT TX rate code 0xff
[183728.043364] ath10k_pci 0000:01:00.0: Cannot communicate with firmware, previous wmi cmds: 36967:18342458 36967:18342450 36967:18342442 36967:18342434, jiffies: 18342760, attempting to fake crash and restart firmware, dev-flags: 0x42
[183728.043480] ath10k_pci 0000:01:00.0: failed to send wmi nop: -108
[183728.063136] ath10k_pci 0000:01:00.0: could not request stats (type -268435456 ret -108 specifier 1)


U-Boot 2012.07 [Standard IPQ806X.LN,unknown] (Oct 03 2018 - 18:59:17)


([[https://zorro.casa/sync/Hosting/Utilities/Development/OpenWRT/issues/3099/2021-05-27%2012-29-38-public.log.txt|Full log available here: 2021-05-27 12-29-38-public.log.txt]])

For the second reboot, a full, proper kernel panic log was provided:

(In hindsight I've probably used the term //panic// incorrectly, as hard reboots might be caused by things other than kernel panics.)


[ 1080.330020] ath10k_pci 0000:01:00.0: htt tx: fixing invalid VHT TX rate code 0xff
[ 6122.017923] 8