[Linux-parport] Checking for bidirectional support

[Jason Curl]

Jason Curl wrote:
> Hello,
> 
> I've scrounged through the web, and I can't find a reliable way in my code to
> test if the ioctl(fd, PPDATADIR, &dir) will set the parallel port to read.

Replying to my own post, for completeness for other people like me, it's 
the TRISTATE flag.

My problems stemmed from using a PCMCIA card, it not working (only the 
feature PCSPP and not tristate).

> 
> As far as I know, all my ports support ECP, etc. and I've configured them as
> such.
> 
> I get PCSPP, TRISTATE, EPP in the kernel messages when ppdev starts (it's a
> loadable module). When I enable ECP from the BIOS, I get PCSPP, TRISTATE.
> 
> I don't see anything obvious in ppdev.h or parport.h that indicates there is
> bidirectional support.
> 
> Thanks in advance,
> Jason.