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xnyle

Slow USB speed on H5 devices (OrangePi Prime) probably cpu-governor related

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Old post below, here is what I found out thanks to some help from linux-sunxi IRC, I think this is a bug in the ondemand governor

 

When using ASIX AX88772B USB to ethernet adapter and the cpu-governor is on ondemand, transfer speed is very slow.

If governor is set to conservative or performance (yes that's right) speed is ok, 50 Mbit at least.

 

So the problem has nothing to do with cpu speed as such (it's working @ steady 480Mhz and @ steady 1200Mhz)

 

for now I'll stick with conservative as I don't want my board to burn up, but It would be nice if someone could take a look at that ondemand governor.

 

Additional info:

 

Changing SMP-affinity on USB IRQs (cat /proc/interrupts |grep ehci_hcd:usb)  also improved performance a bit, but not much, this seems to be missing for OrangePi Prime in /etc/init.d/armhwinfo:

 

      for i in $(awk -F':' '/ehci_hcd:usb/{print $1}' </proc/interrupts | sed 's/\ //g'); do
          echo 2 >/proc/irq/$i/smp_affinity
      done

 

----

 

Is the mainline USB support (4.14.34-sunxi64) known to be slow/ have bugs on H5 devices?

 

I'm using a ASIX AX88772B USB to ethernet adapter (100Mbit) as a second network interface which can hardly reach 13Mbit. Also when using USB keys and copying large amounts of data the kernel sometimes crashes  and until then ksoftirqd uses up to 40% cpu.

A normal usb key (storage device) attached can reach 50Mbit which is not great but ok I guess.

The ASIX adapter itself, works @80Mbit on the Rpi3, so it's not the adapter as such which is causing the problems.

It's connected as high speed device (Driver=asix, 480M)

 

I just would like to know if this is a know restriction/bug, in the current mainline kernel in which case I can just wait.

 

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