Re: [PATCH] usb: udc: add gadget state kobject uevent

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jul 17, 2013 at 10:57:06AM +0300, Felipe Balbi wrote:
> Hi,
> 
> On Mon, Jul 15, 2013 at 11:31:17PM -0700, Greg KH wrote:
> > > The question is since we default GADGET, so the g_mass_storage.ko is
> > > installed early but connecting to a host PC
> > > is randomly, But the udev has no idea when a host PC connects our device.
> > > 
> > > So we consider it's reasonable to let the udev know the GADGET device state.
> > > Is there any alternative to our question?
> > 
> > I thought we already export events for gadget device states, have you
> > looked for them?  I can't dig through the code at the moment, but this
> > seems like a pretty common issue...
> > 
> > Felipe, any ideas?
> 
> we already expose that in sysfs. IIRC udev can act on sysfs changes,
> no ?

If something is polling the sysfs file, yes.  If not, a change event
should be sent to notify people that they need to go re-read it as
something major happened (laptop docked, disk got removed, device
changed state, etc.)

thanks,

greg k-h