If you need to connect more usb function devices to PC host to do usb plug in/out test, you need a good usb hub certified by some orgs. After couples times of physical plug in/out or by pulling up and down D+, usb hub may be down. And PC is another concern that sometimes usb host may be dead after usb function device up and down. You have to power cycle PC to recover usb host ports. So it takes time to find a stable solution from usb hub, pc and OS of PC.
Thomas Tsai ----- Original Message ----- From: "Dave Hylands" <[email protected]> To: "Zac Campbell" <[email protected]> Cc: "Mike Habicher" <[email protected]>, [email protected] Sent: Wednesday, October 23, 2013 3:11:06 AM Subject: Re: [b2g] Software solution for disconnecting the USB cable 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 _______________________________________________ dev-b2g mailing list [email protected] https://lists.mozilla.org/listinfo/dev-b2g
