USB hard drives seem to self-disconnect for no apparent reason
Some background information:
I have two external hard drives connected to my Linux box running Debian Etch (kernel 126.96.36.199)
The two hard drives are 1) a Seagate 160GB external with built-in usb interface and 2) Western Digital 250GB attached to a Dynex usb interface (lsusb reports it is a "Cypress Semiconductor Corp.")
They are attached to a Belkin USB 2.0 PCI interface (NEC chipset according to lspci).
This has happened twice, when I'm copying a large amount of data (first attempt was during a 50GB copy and second during a 100GB copy). During the copy, the operation will fail at some point with numerous errors, an I/O error among them. According to kern.log, the numerous errors are due to a "dead device", similar to what would happen if you unplugged the drive while I/O was in progress.
So, it seems as though at some point the drives are being disconnected. Only thing is, they aren't. I didn't touch them; they are still physically connected! lsusb at this point shows nothing connected, even if i disconnect and reconnect the drives. A reboot seems to fix it.
The earliest usb-related error in the log since my last reboot is this:
usb 1-3: reset high speed USB device using ehci_h
cd and address 2
That appears about four times and then
usb 1-3: device descriptor read/64, error -71
First message appears four times, then it goes back and forth in the logs between the first and second messages. Then:
usb 1-3: USB disconnect, address 2
Then the flood of errors and "rejected I/O due to device being removed" and "Buffer I/O error" and "EXT2-fs error" and "I can't find my inodes" and "You're fscked now" and all that good stuff that happens when a drive is suddenly pulled during I/O.
Funny thing is, I can't access neither hard drive. It's like the PCI USB card dies after that or something.
This never happened when I only had one drive hooked up. Any ideas what could be causing this?