On Tue, Dec 23, 2014 at 12:48:58PM -0600, Felipe Balbi wrote: > On Thu, Dec 18, 2014 at 09:55:10AM +0100, Robert Baldyga wrote: > > Since we can compose gadgets from many functions, there is the problem > > related to gadget breakage while FunctionFS daemon being closed. FFS > > function is userspace code so there is no way to know when it will close > > files (it doesn't matter what is the reason of this situation, it can > > be daemon logic, program breakage, process kill or any other). So when > > we have another function in gadget which, for example, sends some amount > > of data, does some software update or implements some real-time functionality, > > we may want to keep the gadget connected despite FFS function is no longer > > functional. > > > > We can't just remove one of functions from gadget since it has been > > enumerated, so the only way to keep entire gadget working is to make > > broken FFS function deactivated but still visible to host. For this > > purpose this patch introduces "no_disconnect" mode. It can be enabled > > by setting mount option "no_disconnect=1", and results with defering > > function disconnect to the moment of reopen ep0 file or filesystem > > unmount. After closing all endpoint files, FunctionFS is set to state > > FFS_DEACTIVATED. > > > > When ffs->state == FFS_DEACTIVATED: > > - function is still bound and visible to host, > > - setup requests are automatically stalled, > > - transfers on other endpoints are refused, > > - epfiles, except ep0, are deleted from the filesystem, > > - opening ep0 causes the function to be closed, and then FunctionFS > > is ready for descriptors and string write, > > - altsetting change causes the function to be closed - we want to keep > > function alive until another functions are potentialy used, altsetting > > change means that another configuration is being selected or USB cable > > was unplugged, which indicates that we don't need to stay longer in > > FFS_DEACTIVATED state > > - unmounting of the FunctionFS instance causes the function to be closed. > > > > Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx> > > David, can you test it with your setup ? Works fine on my side. Tested-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx> > > cheers > > -- > balbi -- 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
