[Linux-parport] Parport data not tristated after use

Mark Hindley mark at hindley.org.uk
Fri Dec 1 08:30:07 EST 2006


I am trying to use a stk200 type dongle to programme an AVR uC using
avrdude through ppdev. Programming works fine, but after releasing the port
the data lines stay low. This means the 79hc buffer in the dongle is not
disconnected and the uC does not reset. I have to manually disconnect
the cable, which negates the reason for having a buffered dongle in the
first place!

Could I have some advice on why the data lines are staying low, surely
they should become high-Z after release?

I don't think anything is trying to use the port (I have only just
enabled ppdev in my .config)

Hardare is Acer Apsire 1350. Kernel 2.6.18,
parport, parport_pc and ppdev are all modular.
I have tried module params, but they seem to be ignored (PnPBIOS

On load the drivers report:

Dec  1 12:35:37 mercury kernel: pnp: match found with the PnP device
'00:09' and the driver 'parport_pc'
Dec  1 12:35:37 mercury kernel: parport: PnPBIOS parport detected.
Dec  1 12:35:37 mercury kernel: parport0: PC-style at 0x378, irq 7 [PCSPP,TRISTATE,EPP]

As I start progamming I get:

Dec  1 12:35:37 mercury kernel: pnp: the driver 'parport_pc' has been registered

and when programming finishes:

Dec  1 11:15:39 mercury kernel: pnp: the driver 'parport_pc' has been

Let me know what other info would be useful.



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