On Fri, May 24, 2002, Stuffed Crust <[EMAIL PROTECTED]> wrote:
> I've been doing a lot of work recently on the linux-wlan-ng prism2.5 USB
> driver, and I've finally reached the pointw here I have to break down
> and ask for help from someone more familiar with the USB way of things.
> 
> Basically, thanks to firmware bugs in the hardware, it's often necessary
> to reset the device on initialization.  Unfortunately, this caruses a
> kernel oops on some machines.  (and by device reset, I mean
> usb_reset_device() or something similar, ie resetting the port that the
> device is plugged into)
> 
> There are several scenarios here, some work; some don't.. so please bear
> with me.
> 
> All of these cases are with kernel 2.4.19-pre8/i386
> 
> 1) Device plugged in on bootup.
>  a)  Without the device reset, the device does not initialize properly,
>      and unplugging/replugging is necessary.  
>  b)  With the device reset in the driver, on a KT266 (usb-uhci) the
>      devices initializes fine.
>  c)  With the device reset, on an i830m (usb-uhci) we get a kernel oops.
>  d)  With the device reset, on the same i830m (uhci-alt), it initializes
>      fine.
>  e)  With the reset, on an i830m, and the usb-uhci driver, with the
>      device plugged into a hub, it works fine.
> 2) Device plugged in after boot
>      Works fine with either driver. 
> 
> It seems that the way the usb-uhci resets ports on the root hub isn't
> quite sane.  It's also worth noting that the device reset happens insie
> the usb_probe_device context.
> 
> Attached is a dull dmesg output of the boot run with the kernel panic
> using usb-uhci, and the result of passing the oops through ksymoops.
> Uniform CD-ROM driver Revision: 3.12

Just to clarify, uhci-alt worked in every case, but usb-uhci would oops
when resetting the device plugged into the root hub?

JE


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