8.0-RC1: AMD CS5536 (Geode) USB 2.0 controller strange behavour

Eugene Grosbein eugen at kuzbass.ru
Mon Sep 28 03:42:11 UTC 2009

>> I've repeated the test with my USB flash drive formatted as FAT32.
>> It gives the same result: for ICH7-based system I get 26 megabyte/s
>> file writing speed and for AMD CS5536 it suffers from long periods of
>> inactivity while writing data, hence very low awarage writing speed.
>> It seems the root of the problem is in the interaction
>> between USB stack and AMD CS5536 (Geode) USB 2.0 controller
>> and not in media devices themselves.
>> Any more hints please?
> sysctl hw.usb.ehci.debug=15


%sysctl hw.usb.ehci.debug=15
hw.usb.ehci.debug: 0 -> 15
%date; dd if=/dev/zero bs=64k of=/dev/da0 count=100; date
Mon Sep 28 11:25:26 KRAST 2009
100+0 records in
100+0 records out
6553600 bytes transferred in 14.912198 secs (439479 bytes/sec)
Mon Sep 28 11:25:43 KRAST 2009

The log is half-megabyte and is available here (13KB compressed):


> If the USB stack puts the new job into the schedule and the USB controller 
> does not pick it up, it is not an USB stack problem ...

If so, any workarounds possible?

Eugene Grisbeibn

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