On Wed, Jun 11, 2014 at 02:36:27PM -0500, Felipe Balbi wrote: > On Wed, Jun 11, 2014 at 11:29:57AM +0800, Peter Chen wrote: > > On Tue, Jun 10, 2014 at 11:35:07PM -0500, Felipe Balbi wrote: > > > Hi, > > > > > > On Tue, Jun 10, 2014 at 09:10:00PM -0700, Greg KH wrote: > > > > > Let's take USB peripheral as an example, there is a device for > > > > > udc, and a device driver for usb gadget driver, at default, we want > > > > > the device to be bound to driver automatically, this is what > > > > > we have done now. But if there are more than one udcs and gadget > > > > > drivers (eg one B port for mass storage, another B port for usb ethernet), > > > > > the user may want to have specific binding (eg, udc-0 -> mass storage, > > > > > udc-1 -> usb ethernet), so the binding will be established > > > > > after rootfs has mounted. (This feature is implementing) > > > > > > > > Then there better be a way to describe this on the kernel command line > > > > (i.e. module paramaters), right? Which is a total mess, why not just > > > > not bind anything in this case and let the user pick what they want? > > > > > > you can also blacklist all gadget drivers and manually probe them or - > > > get this - you can refrain from using gadget drivers and use libusbg to > > > build the gadget drivers out of raw usb functions, then bind them to the > > > UDC of your liking. > > > > > > > I am just worried if we change the behaviour of using gadget driver, > > can it be accepted by user? If you think it can be accepted if we can > > have some docs, we can implement manually binding for gadget driver > > from now on. > > user shouldn't have to deal with direct module insertion/removal (unless > he's a developer and actually *wants* to do that). Docs are already in > tree. The entire configfs interface has been documented, it's based on > those documents that Matt started writing libusbg. > > -- > balbi Yes, gadget-configfs is a good direction. I would like to know your plan for other gadget drivers (g_mass_storage, g_webcam, etc) All functions will be supported by configfs in future, and current driver will be deleted? - If yes, how to cover the user who still use the old file system? - If no, which binding way for udc and gadget driver will be used? Current binding way for non-configfs gadgets is auto-binding, if we don't want break user's current system, we need to keep auto-binding as the default binding way. With more, we can support manual binding with udc core. I am implementing gadget bus[1], it may not be benefit for gadget-configfs, but is benefit for other gadgets, eg, support loading gadget driver before udc driver, manual-binding between udc and gadget drivers, etc. So, I would like to know if you agree to keep auto-binding for current non-configfs gadget driver as default way (in that way, we can keep current system with no change), and manual-binding can be used by user with module parameters and /sys entry. [1] http://www.spinics.net/lists/linux-usb/msg109015.html -- Best Regards, Peter Chen -- 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
