On Sun, 21 May 2006, Johannes Stezenbach wrote: > On Fri, May 19, 2006, Marcel Siegert wrote: > > a) don't get any kind of e.g. memcopy problems with new structs and old > > kernels after > > this patch went in. so the size of e.g. the tuning params for dvb-s2 can > > be extended > > without having to change the structs size. so also old kernel will > > perform a correct > > memcopy. > > For binary compatibility it isn't sufficient to just add new > fields to struct dvbs2_params. There must also be an indicator > which the kernel can use to see if struct dvb_frontend_params > was prepared by old or new userspace, i.e. if the new fields > are valid or contain uninitialized data. Would this work: Userspace programs must memset the entire dvbfe_params struct to zero. This in effect sets every field to XXXX_IGNORE. Then userspace programs set the fields they know about to their (non-zero) values. If the kernel gets DVBFE_SET_PARAMS and a field is zero, that means the userspace program was using an old api before that field existed. The driver should do whatever it would do before the field was there. _______________________________________________ linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
