Am Donnerstag, 7. Mai 2009 18:29:08 schrieb Alan Stern: > On Thu, 7 May 2009, Oliver Neukum wrote: > > Am Donnerstag, 7. Mai 2009 16:46:11 schrieb Alan Stern: > > > > I haven't yet given serious thought to the API, sorry (probably this > > > > will happen next week) > > > > > > It isn't as simple as it might sound. A program could simply write a > > > hub name and port number to a file. But what format should we use for > > > the hub name? And where should the file be located? Maybe it would be > > > easier if we used the hub's own usbfs device file. But if a program > > > wanted to claim ports on lots of hubs then it would have to open lots > > > of files; is that likely to be an issue? > > > > If you want to get the ports back when the owner dies, you should use > > an fd per port. > > Why? Doesn't a single fd or an fd per hub accomplish the same thing? If you use an fd for more than one port, user space won't be able to transfer ownership. Unix has well thought out and tested facilities for handling access to one resource encapsulated in one fd. One fd per hub has the additional disadvantage of breaking symmetry. It should not matter whether you want one port of two hubs or two ports of one hub. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
