[Linux-parport] Problems in interrupt handler

[vdb128 at picaros.org]

> I am trying to understand the ppdev parallel port driver, specifically
> the interrupt handler.

Your code looks correct.
 
> lspci -nnvv
> 05:08.0 Communication controller [0780]: NetMos Technology PCI 1 port
> parallel adapter [9710:9805] (rev 01)
>         Subsystem: LSI Logic / Symbios Logic Device [1000:0010]
>         Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop-
> ParErr- Stepping- SERR+ FastB2B- DisINTx-
>         Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium
> >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
>         Interrupt: pin A routed to IRQ 17

This is a level sensitive irq and not a triggered AT style irq.  The 
parport_pc module doesn't support level irqs.  They must be disabled 
at the interrupt handler entry since otherwise a screaming interrupt 
occurs.  

http://lists.infradead.org/pipermail/linux-parport/2004-March/000048.html

Just a first guess, Servaas