Re: Problems with IOblix serial ports

["Michael L. Hitch" <mhitch%lightning.msu.montana.edu@localhost>]

On Thu, 20 May 2010, Frank Wille wrote:

> All IOblix devices, the com ports and the lpt ports install a level 6
> insterrupt handler. So when you get an interrupt from one of your com ports
> all handlers (4 x comintr() and 2 x lptintr()) might be called until the
> first confirmed having handled the interrupt.
>
> Which means when the lpt-handlers are before the com-handlers in the isr
> queue, they will be called first and might cause a crash when something bad
> happens (ok, this doesn't explain your success with printf in comintr).
>
>
> > I wouldn't have any way to test an lpt port, anyhow.
>
> I guess nobody ever tested it. I found a message from Ignatios in the
> cvs-log where he wrote that IOblix lpt is untested. But I think he tested
> the serial port without panics.
>
>
> > Any ideas?

  I see one possibility...

  ioblix_zbus.c() sets supa.supio_arg = iobzclock before configuring the 
attached devices.  Then lpt_supio.c sets sc->sc_intack = (void 
*)supa->supio_arg when the lpt device is attached.  The interrupt routine 
does:
        if (sc->sc_intack)
                (*sc->sc_intack)(p);

  Oops...

--
Michael L. Hitch                        mhitch%montana.edu@localhost
Computer Consultant
Information Technology Center
Montana State University        Bozeman, MT     USA