[CentOS] usb irq problem

nate centos at linuxpowered.net
Wed Sep 24 14:09:05 UTC 2008


kira laucas wrote:

> now that you have mentioned it, i have noticed recently that my desktop
> motherboard usb port has gone slower. i mean previously i used to get 28-30
> MB/s transfer speed with my external usb drive. but now the max i get is
> 10MB/s . i have tested the external drive on my friend's laptop and to my
> surprise it transferred with 25MB/s ! is it any indication of any
> potentially disastrous hardware failure issue ?

I wouldn't think the system is about to fail if it's just going
slower. If there are specific error messages that point to it's
failing then maybe. Errors quoted earlier just seem like bad
hardware(perhaps poorly designed or built, rather than hardware
that is physically failing).

Only thing I can suggest is to just verify that the drive is
detected as USB 2.0 via lsusb -v

e.g.
 Bus 004 Device 020: ID 1058:0702 Western Digital Technologies, Inc.
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
[..]
  iManufacturer           1 Western Digital
  iProduct                2 External HDD

I believe the 2.00 indicates USB 2.0, I see several other
devices on my USB that are marked as 1.x

If the device is bus powered, make sure it is getting enough
power, some of my bus powered disks I have to use a USB Y cable
to plug the drives into two ports simultaneously(one for
power+data, the other for power only).

If you configured your system's kernel to ignore the irq errors
as the other poster did(I think your a different poster..didn't
check), you really should remove that option and enable the
checking again, and try a PCI USB expansion card instead and
see if that helps.

nate





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