Re: hotplug TTD

[Keith Owens <kaos@ocs.com.au>]

On Sat, 03 Feb 2001 15:37:06 -0800, 
Miles Lane <miles@megapathdsl.net> wrote:
>So, are we going to attempt to use the persistent module data for any 
>Hotplug related development?  Might this be helpful for giving some
>more consistent mapping of a device node to a physical device resource
>(e.g., /dev/eth0 -> the 3c575 with a particular set of device 
>characteristics -- memory ranges, IRQ, DMA, etc)>

I would be very wary of doing anything like that.  Persistent data is a
good fit for user controlled settings like volume and TV tuner values,
where the worst case is a wrong volume or the wrong TV channel at start
up.

If you use it for critical data such as IRQ then the worst case is the
module does not load.  It will confuse users when the data becomes
obsolete and the module fails to load.  It is not at all obvious where
the insmod data is coming from.

One option does make sense to me.  Use persistent data and rmmod -e to
extract the persistent data to a file.  Because rmmod -e does not
remove the module (it only extracts the data), hotplug can use this
mechanism as a way to extract data from the module and save it.  Then
the next hotplug load can decide if it wants to use the existing data
or not, erasing the saved persistent data before issuing modprobe.

Alternatively hotplug can try to load the module twice, once leaving
the persistent data alone, the second time it renames the saved data
file.  If one works, issue rmmod -e.  If neither work, reinstate the
persistent data file.


_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
http://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel