On Wed, 26 Jan 2005, David Daney wrote:
I have two nearly identical systems running different versions of a MIPS32 based SOC.
On one of them I have no problems. But on the other the usb storage driver seems to be deadlocking.
The linux kernel is nearly identical on the two systems, but there are some differences due to the different versions of the processor.
# cat /proc/version
Linux version 2.4.29Avtrex34 ([EMAIL PROTECTED]) (gcc version 3.4.3) #9 Wed Jan 26 15:24:21 PST 2005
My test is this: I have a 256MB CF card plugged into a USB connected multi-format card reader device. For what it's worth the CF card has a normal vfat file system on it. After it is connected to the system /dev/sda1 corresponds to the CF card. I do cat /dev/sda1 > /dev/null and data is copied for a while, and then the usb storage driver seems to deadlock.
Hints as to the solution to my problems, or pointers as to how to find the problem are appreciated.
This looks like it might be a problem with the usb-ohci driver, not with usb-storage. What happens if you rmmod usb-ohci while things are hung?
Two problems with this approach for me:
1) USB drivers are compiled into the kernel. I can change that, but ...
2) I think I will get a module busy error and not be able to remove it because the stuck program (cat) is using the USB.
What do you think ?
I would beleive the usb-ohci driver / hardware is at fault. I am using the stock driver from the 2.4.29 kernel. What happens if the driver misses an interrupt? Should it eventually time out and reset or something?
David Daney
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