Re: Streaming acquisition from more than one subdevices

On Fri, Jan 14, 2005 at 02:24:58PM +0000, Ian Abbott wrote:
> Frank Mori Hess wrote:
> >It is uncommon for a board's hardware to support more than 1 streaming 
> >read and 1 write subdevice.  I definitely intend to remove the limitation 
> >in comedi eventually though, maybe by having a device file for each 
> >streaming subdevice using sysfs.
> 
> Maybe the 'private_data' member of 'struct file' could be used to store 
> information specific to a particular 'open' of the /dev/comediN device 
> node.  Then the device node could be opened more than once and each file 
> handle set to stream from a different subdevice.  In theory :-))

It's a UNIX limitation.  Comedi jumps through some pretty
nasty hoops already to be able to stream both input and output
on the same device file.  There's no real reason for sticking
to one device file, other than changing it would be incompatible.



dave...

Received on 2005-01-15Z18:09:57