Over-current on port x *** SOLVED******

OrangeRoot1000 · 2010-01-16 15:42:21

Hey all I just bought a Samsung external usb dvdrw/cdrw device. It is powered by 2 usb connections in a Y plug. However, dmesg reports the above error about over current issues and the device won't work. I've tried taking out the "smaller" usb cable which would be the extra power umph for other machines that have lower powered usb hubs.

Looking around in Searchalot the posts I find are spanning back from present to 2000 ish with the same error and no fix. I even set my BIOS USB setting to disable legacy USB. Is there any fix for this? I should either get a powered hub today and try it or get an RMA because my time is almost up to return it. Prompt replies welcome.

Last edited by OrangeRoot1000 (2010-01-17 02:59:46)

xaos5 · 2010-01-16 22:46:32

That means either the usb product is defective (very very unlikely but possible) or your usb on your computer can't supply enough power to the device and its actually reporting it as so (which usually doesn't happen unless its drawing a lot of current). FYI laptop usb ports tend to not meet the spec for usb (500mA per port). I'd try a powered hub and if that doesn't work its defective. DONT PLUG THIS INTO other ports or other computers hoping it will work... not all usb ports are protected like they should be.

ewaller · 2010-01-16 23:51:03

USB devices are supposed to negotiate with their host as to how much power they may draw. The 500mA number is available only after the device has asked for, and received permission to use that much current.

You had stated there is a 'y' cable -- does this go to two ports on the host? I hope the device negotiates for power on both ports. I would be curious to know what is reported by lsusb -v after the device is connected and is working.

The overcurrent message originates with the USB controller indicated the external device has drawn more current than in requested or was given permission to use. This is a hardware fault condition and should not be a function of which OS you are running.

I second the motion for a powered hub.

OrangeRoot1000 · 2010-01-17 02:58:53

Update:

I was figuring that too much current was being drawn from the laptop to the device. As far as I can tell there is no damage whatsoever and there were 0 sparks/static buildups either way. The solution is definitely an AC adapter either purchased with one in the usb dvd/rw OR a AC powered usb hub... i went the hub route

. It's a great little dvd/rw and small so I hopeI get plenty of mileage out of it.

As far as lsusb... the error was say

blah blah over-current on port 5

lsusb would show port 5 but nothing connected.

dmesg just reports the over current and can stop a machine from booting until the plug is removed from the offending device.

VP

xaos5 · 2010-01-25 08:29:57

ewaller wrote:

USB devices are supposed to negotiate with their host as to how much power they may draw. The 500mA number is available only after the device has asked for, and received permission to use that much current.

*supposed to negotiate* but I haven't seen this actually done ever. It seems most usb host ICs will just give as much current to a device it can supply. By Specification each port (I believe) should be capable of 500mA but I think they will allow one port to draw over that due to design. A good example would be my phone was able to source 1000mA from one port and it never caused a problem.

On a side note I've actually tried to set the MaxPower attribute the controller reads to around 1-10mA and it never complained. So his message to me is the USB chip is at its limit for current draw by design not limited by software.

OrangeRoot1000 · 2010-01-25 15:54:01

When I ws talking to my brother in law, he mentioned that the manufacturers started adding a second plug, making it a Y and that for the most part settled the issue especially in Macs. The hub works great as does the DVD drive, and its compact like I need it to be so when lugging around stuff it's not super heavy.

Arch Linux

#1 2010-01-16 15:42:21