Re: [linux-usb-devel] Re: RFC: [2.6 patch] let BLK_DEV_UB depend onEMBEDDED

From: Alan Stern
Date: Mon Dec 20 2004 - 10:41:41 EST

On Sun, 19 Dec 2004, Pete Zaitcev wrote:

> I don't quite understand why it matters for you if a certain module
> is loaded or not loaded. The hotplug acts upon the contents of
> modules.usbmap which does not change when you modprobe or rmmod things.
> So, the match lists are made non-conflicting between
> ub and usb-storage. It looks as if Adrian has the same broken mental
> model of the way things work. Once again, what is loaded does not
> matter (not in ideal world, but in reality we still have conflicts such
> as e100 and eepro100).

No one has posted a reply to this point, so here's one even if it is

What matters is not which modules are loaded, but rather which modules
bind to which devices. If ub is configured then usb-storage will not bind
to certain devices, regardless of what modules are loaded.

Problems start arising when devices that ub binds to and usb-storage
doesn't (when ub is configured) fail to work with ub, or work much more
slowly than they do with usb-storage. And since some distributions enable
ub in their shipping configurations, users often don't realize what has
happened -- they only know that things don't work as well as they used to.

Maybe a reasonable answer would be to ask distributors not to enable ub,
and leave it up to individual users to configure it when they want to.
That is the default setting in Kconfig, after all.

Alan Stern

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