LinLog

Today I discovered an extremely inconvenient bug in Kubuntu Edgy. It's a problem with a USB mass storage device that only occurs under the 2.6.17 kernel.

I have this USB flash drive that I bought this summer. It's a little unusual in that it came with two partitions on it. One is a bootable (I think) 1.4MB partition and the other is allocated the remainder of the 1GB drive capacity. On Windows, the boot partition is detected as a USB floppy drive, while the main data partition is picked up as a standard USB mass storage device. In Kubuntu Dapper, both partitions were detected as USB mass storage volumes and mounted when the drive was inserted.

When I plugged that drive into my external USB hub today, it didn't work. And by "didn't work," I mean it didn't work at all. No auto-mount, no desktop icon - udev didn't even create a freakin' device node. I checked the output of dmesg and lshal, and it seems that the drive was detected as some kind of generic USB device. In fact, dmesg only reported a "new full speed USB device using uhci_hcd and address 12." No mention of any device nodes, drivers, or anything else. Just a notice that the device was not plugged into a high-speed hub.

I don't yet know what the problem is, but it seems to be at least partly in the kernel. How do I know this? Because, on a hunch, I tried rebooting and running with the 2.6.15 kernel I still had installed from Dapper. When I did that, the device worked. It seemed a little slow, but it worked.

It's important to note that this problem only occurs with the one drive. I have an old single-partition 32MB Lexar flash drive and that functions perfectly under Edgy with kernel 2.6.17. I'm guessing the problem is something about that weird two-partition setup. I don't know why that would cause a problem, but it's all I can think of at the moment.