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SubjectRe: [PATCH v5] usb: gadget: f_fs: add "no_disconnect" mode
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@samsung.com>
>
> David, can you test it with your setup ?

Works fine on my side.
Tested-by: David Cohen <david.a.cohen@linux.intel.com>

>
> cheers
>
> --
> balbi




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