I was testing the USB capabilities of the au1500 and discovered that
when a USB flash drive is removed during a copy operation twice, the
USB host controller/root hub will no longer detect if the device is
plugged in a third time. I am assuming there is a bug in the au1xxx
parts of the USB drivers because Linux has been able to handle this
case for some time with the standard EHCI/OHCI/UHCI host controllers.
I am testing using the dbau1500 development board and the 2.6.12
kernel with the fs in ram.
I would be interested if anyone has experienced anything similar with
the au1500 and the 2.6.12 or other (earlier or later) kernels.
The test goes something like this:
Plug in the USB drive - it gets detected.
(it does not seem to matter whether the drive is mounted or not, I
tested both ways.)
At the command prompt:
#dd if=/dev/zero of=/dev/sda bs=1k count=50k
after some time un-plug the drive.
Error messages (too many to post)
Third time device is not detected.
I did not want to post a huge list of error messages, but I did notice
differences between the first and second try.
In the first, I got a lot of "rejecting I/O to device being removed"
from scsi, while after the second removal I did not. Instead I got a
lot of "Buffer I/O error on device sda" from scsi.
I am actively looking in to the problem and wanted to post to the list
in case someone else had come across this behaviour. I could list the
error messages if anyone is interested.
Any feedback would be appreciated.