USB: insufficient power available to use all downstream ports

ezacaria · 2011-06-21 13:20:26

Hi,

I've recently started having a problem with my USB sound card.
I normally connect it to one of the USB ports of my monitor. This worked fine until couple of days ago when I upgraded from 2.38 to 2.39

I get the following from dmesg:

[    4.996817] usb 2-6.6: new full speed USB device number 6 using ehci_hcd
[    5.094415] usb 2-6.6: rejected 1 configuration due to insufficient available bus power
[    5.094419] usb 2-6.6: no configuration chosen from 1 choice

The strange thing is that the same port can run an external USB drive easily, so it is not really a limitation of available power.
The card runs fine if I plug it in a port of the desktop tower:

[ 1141.983235] usb 3-2: new full speed USB device number 2 using uhci_hcd
[ 1142.149008] input: USB Audio as /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.3/input/input8
[ 1142.149127] generic-usb 0003:0CCD:0028.0005: input,hidraw4: USB HID v1.00 Device [USB Audio] on usb-0000:00:1a.0-2/input3

I was going to downgrade the kernel to check if the problem goes away, but I cleaned the cache before the last upgrade.

Any ideas?

Thanks!

Eduardo

ewaller · 2011-06-21 15:10:49

On USB buses, devices must negotiate with their host as to the amount of power they are allowed to draw. Disk drives are notorious for ignoring that inconvenient little part of the USB specification; Many brands draw whatever they please (Often even using a 'Y' cable).

Different hosts behave differently. Some detect over-current and reset the bus, others just grunt it out until a fuse (or wire, or connector) blows.
In your case, I bet the disk drive ignores negotiation and plows ahead, whereas this other device plays by the rules.

Just to be sure, can you post the output of lsusb -v

Arch Linux

#1 2011-06-21 13:20:26

USB: insufficient power available to use all downstream ports

#2 2011-06-21 15:10:49

Re: USB: insufficient power available to use all downstream ports

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