On Thu, 2011-02-03 at 15:00 -0600, Jeff Epler wrote: > Oh, I think I understand better what you're asking now. > > Are you asking whether a hardware driver that uses a parport must be > built on the hal component called "hal_parport"?
Not really. > Absolutely not! The > interface of hal_parport (17 or so 'bit' pins that can be read or > written once per period) is pretty inconvenient for lots of > sophisticated parport-attached devices, such as any EPP device. > > However, your driver *should* use a port registration method This is what I was looking for. > (the best > being hal_parport_get, which internally uses whichever lower-level > method is appropriate, parport_find+parport_claim or request_region) in > order to make sure that while emc is running, only one device is trying > to access those low-level port addresses. > > Jeff My thinking is that the drivers I've looked at require the user to supply a base port address. The only way two drivers could try to use the same port resources would be if the user typed in the same address for both drivers by mistake. A printer on a normal Linux PC would be different because it can negotiate the resources with Linux and the user just prints to the printer's name. I suppose EMC2 could do the same but ... I think I got an ah ha. I could enter 0 or 1 into the driver config, then hal_parport would assign a known port to the driver, then it would be up to me to find which port to plug the device into. I don't think I've ever seen an example config file that does that. Is this worth the extra complexity? I suppose if I don't write my driver to comply I could break any other driver that does comply and uses some form of automatic resource assignment. This also hints that I should write two drivers, a generic parallel port driver and a separate peripheral device driver. Thanks for the help Jeff. UPS just got here with my Sunix card, gotta go. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ The modern datacenter depends on network connectivity to access resources and provide services. The best practices for maximizing a physical server's connectivity to a physical network are well understood - see how these rules translate into the virtual world? http://p.sf.net/sfu/oracle-sfdevnlfb _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
