parport_pc problems/strange behavior

parport_pc problems/strange behavior

[Sebastian Jesse Bronner]

Hi,

I was just installing a PCI parallel port card (StarTech PCI2PECP).  In 
the process, I noticed that while loading parport_pc without arguments, 
detects the built-in parallel port nicely, trying to specify that 
parallel port on the command-line doesn't work:



[modprobe parport_pc]
pnp: Device 00:17 activated.
parport: PnPBIOS parport detected.
parport0: PC-style at 0x378 (0x778), irq 7, dma 3 
[PCSPP,TRISTATE,COMPAT,EPP,ECP,DMA]



[modprobe parport_pc io=0x378 irq=7 dma=3]
parport 0x378 (WARNING): CTR: wrote 0x0c, read 0xff
parport 0x378 (WARNING): DATA: wrote 0xaa, read 0xff
parport 0x378: You gave this address, but there is probably no parallel 
port there!
parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE]



Modprobing parport_pc without dma or irq results in the same message 
except that when no irq is specified, it makes up some bogus irq, like 
-825114668.

Practically, what this means for me is that I can either run the ports 
on the parallel port card or the built-in parallel port, as the ones on 
the card require manual specification

modprobe parport_pc io=0x378,0xbc00,0xb800 irq=7,10,10

where the first, of course, refers to the built-in parallel port, and 
should activate it, but doesn't.

All this leads me to believe that I'm not telling parport_pc enough 
information---perhaps it has to do with pnp.  If any of you have seen 
this before and understand this behavior of parport_pc, I would be very 
happy to see your answer.

Cheers,
-- 
Sebastian J. Bronner
waschtl@sbronner.com