Re: [PATCH] hotplug usb.rc changes

[David Brownell <david-b@pacbell.net>]

Olaf Hering wrote:
>  On Sat, Jun 07, Olaf Hering wrote:
> 
> 
>>Index: etc/hotplug/usb.rc
>>@@ -154,32 +134,16 @@
>>     # FIXME: some of this should be driven by PCI hotplugging, and have
>>     # the blacklist control which uhci driver gets used (before 2.5).
> 
> 
> This comment looks like a chicken/egg problem.
> if you load the usb hostcontroller drivers via pci.rc then we will lose
> the real hotplug events because usbfs is not mounted.

Unless something guarantees the "mount /proc/bus/usb" step gets
done after "usbcore" loads.  There are modules.conf and modprobe.conf
ways to do that ... or doing it in "usb.rc" while bringing USB up,
as is done here, not pretty but reasonably robust.


> We can still syntesize stuff, but thats probably not what hotplugging
> means?

If "usbcore" is live, then real hotplugging events will happen.

But they may not be all that useful ... if a USB keyboard needs
to be available early, that means hotplug events happen early.
Even before filesystems are mounted or networks are up, so
the more interesting hotplug agents can't do their work.

If nothing else, a "coldplug" synthesis phase later on will
make sure that the agents will be called when most system
resources are available.


> Has anyone looked into this?

Not lately.


- Dave




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