Subject: Re: [PATCH] ar9170usb: add mode-switching for AVM Fritz!WLAN USB N
 devices in cdrom mode
From: Dan Williams <dcbw@redhat.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Frank Schaefer <schaefer.frank@gmx.net>,
	Matthew Dharm <mdharm-usb@one-eyed-alien.net>,
	linux-wireless@vger.kernel.org, linux-usb@vger.kernel.org
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Date: Mon, 02 Nov 2009 13:45:59 -0800
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On Mon, 2009-11-02 at 21:05 +0000, Alan Cox wrote:
> > apparently do use the driver CD thing to send Linux drivers and software
> > to a few clients.  But by and large, the driver CD is completely
> > useless.
> 
> And then every so often you need to rummage around the driver CD image to
> extract the APN or other data you need to make your modem work. At which
> point you end up having to recompile the kernel to get it. Very annoying
> given it could be trivially done properly in user space.

Maybe there's a better way as I said a bit lower in the thread; could we
put the logic for ejection into the driver (and not usb_modeswitch or
whatever) but put the decision into userspace in udev?

Right now the kernel drivers know what hardware they support, and that's
a great place to also put how to eject the fake driver CD.  So the
mechanism could live in the kernel still (instead of in usb_modeswitch
in userspace) while the actual decision still gets made in userspace
with udev rules.  The rules would say something like "if this USB
storage device has an 'fakecd' attribute, then touch the 'ejectmeharder'
attribute" instead of complex rules to run usb_modeswitch that duplicate
all the device IDs in userspace.  If you need to rummage around on the
driver CD for whatever reason, you disable the udev rule.  Maybe?

I simply hate the duplication of all the device IDs with one set in the
kernel and one set in userspace because it's pretty pointless and makes
twice the work when new hardware comes out.

Dan