Hi.
As I mentioned in the subject I am running a 4.14.15-rt13 kernel. The
hardware is a RK3288 SoC and this combination is producing a heavy CPU
load when an USB Bluetooth controller is simply powered on without the
need of connecting to any device.
I am running bluez5 (5.46).
This is what it looks like:
92 2 root RW 0 0% 20% [irq/45-dwc2_hso]
91 2 root RW 0 0% 11% [irq/45-ff540000]
Above is the USB interrupts of the controller where the USB bluetooth
device is connected and it is simply power on without doing anything.
Turning the controller off:
[bluetooth]# power off
Changing power off succeeded
[CHG] Controller 00:15:83:EA:73:23 Powered: no
[CHG] Controller 00:15:83:EA:73:23 Discovering: no
[CHG] Controller 00:15:83:EA:73:23 Class: 0x000000
And the CPU load is down to minimal:
92 2 root SW 0 0% 2% [irq/45-dwc2_hso]
91 2 root SW 0 0% 2% [irq/45-ff540000]
I have tried two different USB Bluetooth devices:
Bus 001 Device 003: ID 0a12:0001 Cambridge Silicon Radio, Ltd
Bluetooth Dongle (HCI mode)
Bus 001 Device 005: ID 0a5c:4500 Broadcom Corp. BCM2046B1 USB 2.0
Hub (part of BCM2046 Bluetooth)
With the same result. I have also tried running a WLAN USB device and
this does not produce any high CPU load. So fairly isolated to USB
Bluetooth.
I have tried running a 4.14.15 vanilla kernel, and this does not have
this problem which means that it is the following combo
RT + USB Bluetooth
That seem to the problem.
Before I start digging deep in to the stacks I wanted to post my
problem to the community to see if someone is having a similar problem
on a different hardware or if you have any pointers on how to further
debug this.
--
Med Vänliga Hälsningar / Best Regards
Mirza Krak
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