Comment 455 for bug 88746

Tested on two computers & different usb hardware & hd's.

An 8.04LTS install developed this problem. I tried a 8.1 Live CD with 2.6.27-7-generic which worked as expected.

The fresh install of 8.1 worked until updated less than an hour later after installing all the latest updates (inc 2.6.27-9-generic), booting from previous kernel -7 from grub does not fix the problem (same in 8.04LTS) uname reports kernel -7 & rebuilding initrd is -9 not -7?

setting max_sectors seems to make a difference.

sudo modprobe -r ehci_hcd / blacklist doesn't seem to do much on 8.1, as It still seems to be using it:
usb 4-2: new full speed USB device using uhci_hcd and address 4

HD log while copying large files 10GB + backups: time it takes goes from minutes to days,,,, copying freezes before usb reset

usb 5-8: reset high speed USB device using ehci_hcd and address 7
sd 9:0:0:0: [sdf] Sense Key : No Sense [current]
sd 9:0:0:0: [sdf] Add. Sense: No additional sense information
usb 5-8: reset high speed USB device using ehci_hcd and address 7
sd 9:0:0:0: [sdf] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK,SUGGEST_OK
__ratelimit: 1451 callbacks suppressed
lost page write due to I/O error on sdf1
JBD: Detected IO errors while flushing file data on sdf1

Probably related: USB dvd writer is recognised sometimes and appears to work occasionally goes really slow. or just produces reset error with increasing address number. sorry haven't got round to test, as I am more interested in getting a reliable working usb hd backup.