Re: Is libusb dead?
Oliver Neukum <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
Am Dienstag, 24. April 2007 01:32 schrieb Greg KH: > On Tue, Apr 24, 2007 at 01:24:02AM +0200, Oliver Neukum wrote: > > Am Dienstag, 24. April 2007 00:35 schrieb Greg KH: > > > > This suggests that usbfs2 should have special "interface" files as well as > > > > a special "device" file and "endpoint" files. > > > > > > Nah, I don't think that will be needed. > > > > 1. Interfaces have properties, namely the setting > > Yes, which we should be able to control through the control endpoint > with an ioctl, right? No, because then we'd have to continue giving access to the whole device if we want to drive only an interface. The 0 endpoint must be replicated for each interface, which is in effect the "interface" file Alan is talking about. Plus, there are situation where some requests to endpoint 0 must fail and others must work. > > 2. We cannot operate solely at the level of the endpoint > > We must know which requests are affected when an interface > > is affected, eg. reset cannot restore the altsetting. This cannot work > > at the endpoint level because endpoint 0 is shared. We cannot drop > > claiming an interface as is done in the current usbfs. > > Once you open an endpoint that is not endpoint 0 that would signify that > the interface is then "claimed" as far as the kernel goes, right? That's not enough. The kernel must have a notion of _who_ owns the interface. As a task may own several interfaces, the action must be explicit. Besides, an interface is not required to have endpoints, nor should a task be required to open an endpoint just for show. You are designing a kludge. Regards Oliver ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel