MacBook Pro USB Port Issues

I've noticed recently that I can't seem to mount any USB drives using the second USB port (farther from the screem) on my MBP. The first port (closer to the screen) seems to work fine. I can mount my USB thumb drives and external hard drives using this first port, but none of them seem to mount using the second port. I was pretty certain it was a hardware issue, but the USB port seemed to be at least poweing the external hard drives (light would come on). So i tested a mouse and a mouse works just fine.Then i tried plugging in my iPhone. That started charging immediately and opened iTunes and I could see my phone in iTunes. So the USB port doesn't seem to be completely broken, it just doesn't seem to want to play nice with external storage. Is there any software/firmware issues that would be causing this issue? any help would be great.

btw, I have 15-inch, Mid 2010 MBP (MacBookPro6,2), with a 2.66 GHz i7 processor. I'm running 10.7.3, and just did a software update.

thanks

-scott