Re: usb device not showing up

[Alan Stern]

On Tue, 4 Nov 2008, Norbert Preining wrote:

> On Di, 04 Nov 2008, Alan Stern wrote:
> > > - First booting Vista, then RE-booting (not turning it off in the
> > >   meantime) into linux gives me that device and everything works.
> > 
> > By "it", did you mean the laptop or the modem?
> 
> I meant: 
> - first booting vista, then re-booting ... the device shows up (and is
>   functional)
> 
> - booting from off state the device does not show up and cannot be
>   switched on using /sys/devices/platform/sony-laptop/wwanpower
>   (although the behaviour that it can be switched on using the above
>   sysfs file is documented)
> 
> > No.  I'm interested in seeing the usbmon output for when the modem is
> > first detected by the USB subsystem.  During a normal boot this will 
> > happen before you can start usbmon.
> > 
> > If you can't boot with the modem off, then try this instead: Unload 
> > ehci-hcd, uhci-hcd, and ohci-hcd, then start up usbmon (copy the 0u 
> > file) and reload whichever driver the modem attaches to.
> 
> Ok, I will recompile my kernel with USB as modules and do the above. Is
> there a way to tell the kernel not to load any device drivers/modules
> (probably overriding modprobe in some way)?

You can add entries to /etc/modprobe.d/blacklist.  But for temporary 
testing, it might be easiest simply to rename the module files 
themselves (under /lib/modules/.../kernel/drivers/usb/host) so that the 
hotplug system can't find them.

Alan Stern

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