USB via module instead of kernel?

Jesse Sheidlower jester at
Tue Apr 13 07:49:58 PDT 2004

On Mon, Apr 12, 2004 at 10:34:13PM -0400, Jesse Sheidlower wrote:
> I'm new to this kernel-module thing, so I hope this isn't
> a silly question.
> I'm using FreeBSD 5.2 on a laptop running ACPI, and like
> many others have had suspend/resume problems with the 
> USB dying on resume. I saw a suggestion somewhere that
> you could remove USB support from the kernel, and add it
> in via a .ko file at boot time; this way, you could have
> an rc.suspend and rc.resume that unloads/loads the USB
> module appropriately and perhaps avoid the problems.
> I'm not entirely sure how to do this. First, I note
> that the "device usb" line in the kernel configuration
> file has a "Required" note in it, and I'm nervous about
> removing something that says "Required".
> Second, while I have a usb.ko file under /boot/kernel/, if I
> type "kldload usb", I get a "can't load usb: File exists"
> message, but if I try "kldunload usb", I get "can't find file
> usb: No such file or directory". I might have expected a
> different message if usb is loaded as part of the kernel. If I
> want to enable it at boot, do I just add "usb_load="YES"" to
> /boot/loader.conf ?
> So to summarize, I guess my questions are:
> 1) Can I comment out "device usb" from my kernel config and
> then rebuild the kernel, without causing some big problem?

Responding to myself, the answer is "no"; removing "device
usb" from the kernel config causes errors at "make", so
I had to go back.

I still can't seem to load or unload usb as a module. Any
suggestions welcome.

Jesse Sheidlower

> 2) To load at boot, do I just add "usb_load="YES"" to
> /boot/loader.conf ?
> 3) Will doing what I described help with the USB problems
> on suspend/resume?

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