- From: David Schleef <ds_at_schleef.org>
- Date: Wed, 30 Apr 2003 12:34:24 -0700
On Wed, Apr 30, 2003 at 04:00:44PM +0200, Herman Bruyninckx wrote: > > What is the exact aim/meaning of the comedi_event() function in > comedi_fops? It handles all events that have been generated and > stored in the s->async->events flag? > > The last "mask" argument of the function call is an integer, which is > almost immediately overwritten before its value is used... > Apparently "mask" is used as "s->async->events", which is a global > variable and hence need not be given as argument in the function > call. (So, can "mask" disappear from the comedi_event prototype?) > If I am wrong here, where can I find the exact meaning of this mask > flag, and of all the events that this command must/can service? In the past, almost every driver had a separate variable to keep track of the event mask before comedi_event() was called, essentially duplicating s->async->events. This was rather silly, so the drivers (and comedi_event()) was changed to use s->async->events directly. Unfortunately, the cleanup step of removing the parameter from the comedi_event() prototype was never done. It should be done now. > Another point: callbacks can only be done when the subdevice has > commands? This is not illogical.... Yes. > Finally, the INTTRIG instruction carries a third numerical argument; > what is the meaning of it? Encoding of driver-specific trigger > identification? It is for future use. It should be set to 0 by the application, and the driver should return -EINVAL if it is not 0. dave...
Received on 2003-04-30Z18:34:24