[arch-general] Unable to mount external USB HD from two of my USB ports

I've been having troubles mounting an external USB HDD to two of the three USB ports on my laptop. dmesg reports a timeout connecting to the device; plugging in other devices to the same ports works fine with no errors. I've attached the log here[1]. The drive in question is a Seagate 1.5 TB Expansion Portable Drive, model ST1500LM003-9YH148. I reformatted it upon purchase to have two partitions, a NTFS one for Windows compatibility, and an Ext4 one for Linux backups and miscellanea. Each partition is ~750GB in size. Any idea what is going on? I think the issue may be with the drive, which is virtually brand new (I bought it ~3 months ago). [1] https://gist.github.com/3916478