Re: xircom cbem56g-100 support

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

> > Workaround:  comment it out of that blacklist.  
> 
> it now works.

As should be ... :)

> another quick question:
> 
> this is a multifuntion card and hotplug loads the network driver, but is
> hotplug or cardmgr responsible for loading the serial driver (esp. since
> i'm testing the in-kernel pcmcia drivers and that means just loading the
> regular serial.o module)?

If this is done with multiple PCI functions, then I'd expect normal
PCI hotplugging to trigger loading the right module.

If the serial function isn't exposed using a PCI function (that is, if
"lspci" doesn't show it) then hotplugging could load "serial.o" by
adding a /etc/modules/pci.handmap functionality ... assuming that
cardmgr is really trying to be ignorant of this card.  That's quite
possibly a gap in the current cardbus hotplug support.  (Want to
implement such support?)


> and finally, there seems to be a disadvantage of hotplug at this point:
> 
> with pcmcia-cs, if you tried to do a cardctl eject when the interface was
> still UP it would return a "ioctl(): Device or resource busy." with
> hotplug, since cardmgr doesn't do the configuration, you can eject a card
> that still has a live interface. i know people should know better. does
> hotplug have functionality similar to "unconfigure and remove?"

I don't know of a good solution for such problems.  As I recall,
"cardmgr" and "cardctl" interact through some sort of state that
records driver/hardware bindings.  Using just "modutils", that sort
of functionality doesn't exist.  The lack shows up in other places;
it's why hotplugging doesn't have an automated way to "rmmod".

What's needed is IMO a generic mechanism that can work for USB,
PCI/Cardbus, and other kinds of hotpluggable drivers.  It should
happen automatically when the hardware is removed.  Presumably
there should be a software-driven version like "cardctl eject", to
support cleaner device shutdown protocols.

And when power management suspends the host, the clean shutdown
should kick in (devices get removed then).  I know that USB needs
some new kernel driver hooks to handle that, we know roughly what
they need to be, but I suspect those new APIs won't get added till
the 2.5 work starts. (Backport should be easy, but every HC driver
needs updating.)

- Dave




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