The way that USB detects that the device is present is through a pull-up/down resistor on D+/D- line(s) - I can't remember the exact details, but its in the USB spec.
Devices I've worked with in the past sometimes have a MOSFET on the resistor, which is controlled by a GPIO line, which can allow the resistor to be disconnected, which then acts like a cable pull as far as the host is concerned. You'd need to find out from the phone manufacturer if their device has such a gpio line. Dave Hylands ----- Original Message ----- > From: "Zac Campbell" <[email protected]> > To: "Mike Habicher" <[email protected]>, [email protected] > Sent: Tuesday, October 22, 2013 3:11:23 AM > Subject: Re: [b2g] Software solution for disconnecting the USB cable > > That seems pretty heavy for our test suite. I think we can just do `adb > restart` via mozdevice and get a similar effect I think. > > We're still not sure if we'll write this test, hard to validate it on > the host side. Some more experimentation needed. > > > > > > On 16/10/13 18:39, Mike Habicher wrote: > > I haven't tried these methods, but it should be possible to do a soft > > reset of the device from the host end. A couple of approaches: > > http://marc.info/?l=linux-usb-users&m=116827193506484 > > http://permalink.gmane.org/gmane.linux.usb.general/55298 > > > > --m. > > > > > > On 13-10-16 01:18 PM, Zac Campbell wrote: > >> We want to write an automated test for enabling USB Mass Storage but > >> we have a problem in the teardown of the test in that turning off USB > >> Mass storage requires the cable to be removed from the device. > >> > >> Restarting the b2g process does not do the trick. 'adb reboot' works > >> but is a bit heavy for a test teardown. > >> > >> Does anybody know of a software method we can use to do this teardown > >> cleanly and quickly? > >> > >> Thanks > >> Zac > >> _______________________________________________ > >> dev-b2g mailing list > >> [email protected] > >> https://lists.mozilla.org/listinfo/dev-b2g > > > > _______________________________________________ > dev-b2g mailing list > [email protected] > https://lists.mozilla.org/listinfo/dev-b2g > _______________________________________________ dev-b2g mailing list [email protected] https://lists.mozilla.org/listinfo/dev-b2g
