RT-BE92U only Core 1 is visible

[Manuel_p]

I just got this router today, and I’ve been working through the setup process, including the firmware update. This is the second Asus router I’ve owned, and something caught my attention. After some time configuring the router, all the CPU cores disappeared except for one.

I tried restarting and resetting it, but it's like they’re gone. Any ideas?

[cowhow]

Mine did exactly that.  I resolved mine my turning the router off, unplugging the router's power and then, leaving power unplugged, turning the power switch back on leaving it for 2 or 3 minutes. Mine rebooted itself, took a very long time to come up and did so with only one core.  

[Manuel_p]

Thank you, but I tried unplugging all the cables and power for 5 minutes, turning the switch off, plugging everything back in, and turning it on, but nothing—still only one core.

Did you only do that? or I missed something?

[Manuel_p]

Ok, this was my entire workaround.

• I tested this versions: 3.0.0.6.102_37523 -> Only 1 core working (unable to reinstall it as it seems corrupted on the ASUS website).

• 3.0.0.6.102_37506 -> Only 1 core working.

• 3.0.0.6.102_37504 -> All 4 cores working!

And when the cores were offline, I found this in the log:

broadcomThermalDrv 8106037c.brcm-therm: init chipId 0x6765 (CPU cnt present 4 online 4 possible 4 active 4)
thermal cooling_device0: take CPU#3 offline
IRQ 17: no longer affine to CPU3
IRQ 18: no longer affine to CPU3
IRQ 21: no longer affine to CPU3
IRQ 22: no longer affine to CPU3
IRQ 23: no longer affine to CPU3
IRQ 24: no longer affine to CPU3
CPU3: shutdown
psci: CPU3 killed (polled 0 ms)
thermal cooling_device0: take CPU#1 offline
CPU1: shutdown
psci: CPU1 killed (polled 0 ms)
thermal cooling_device0: take CPU#2 offline
CPU2: shutdown
psci: CPU2 killed (polled 0 ms)

So I decided to check what was wrong inside. I connected to both 37506 and 37504 versions through SSH, and this is what I found.

New version (37506):

The temperature reading gave me this value:

root@RT-BE92U-2060:/# cat /sys/class/thermal/thermal_zone*/temp
18981107

And only 1 core enabled, with 3 disabled:

root@RT-BE92U-2060:/# cat /sys/devices/system/cpu/cpu*/online
1
0
0
0

At this point, I thought it might be some kind of power-saving feature, so I stressed the CPU to check if the router would wake up some of the cores, but nope.

I executed:

while true; do true; done &
while true; do true; done &
while true; do true; done &

And after seeing no changes in the number of enabled cores, I closed the process:

killall sh

Then I jumped to 37504 (the old one):

Aside from immediately seeing all 4 cores working, what caught my attention was the temperature reading:

root@RT-BE92U-2060:/# cat /sys/class/thermal/thermal_zone*/temp
62120

So it looks like versions 37523 and 37506 have some kind of bug, as they report the temperature as 18981107 vs 62120 in the working version.

If 62120 corresponds to something like 62ºC, then 18981107 would be... 18,981ºC?

I understand that there is a bug in versions 37523 and 37506 that causes the temperature sensor to read incorrect values, which then disables the cores for protection.

I’m leaving this here in case it helps someone in the future, and I hope upcoming versions fix this issue

[JonathanE]

 I have the same issue after the firmware update so I downgraded to 37504.