On Thu, 10 Oct 2013, Felipe Balbi wrote: > On Tue, Oct 08, 2013 at 10:28:29AM -0400, Alan Stern wrote: > > Felipe: > > > > I've got an Android device that uses the omap2430 musb driver. It's > > configured to go into device mode when it starts up, which I guess is > > the normal thing for Android devices to do. > > > > Can you explain how to switch the controller over to host mode (and > > back)? I tried writing "host" to the sysfs "mode" attribute, but all > > that happened was an immediate crash and reboot. > > grounding ID pin should be enough. I can't ground the ID pin. The USB port is exposed through a proprietary connector and cable; the far end of the cable has a normal (not micro) type-A plug. (In case it matters, the device is a Nook HD.) > If you're getting a crash when > switching through sysfs, it's likely a bug in that kernel. Can you share > the crash ? There's nothing to share. The device's screen goes all black and a reboot begins right away. Admittedly, this is a pretty old kernel (3.0 vintage). Barnes & Noble doesn't upgrade the the software for their devices very much. > > (Related to this, it is notable that the omap2430_musb_set_mode() > > routine ignores its second argument, musb_mode. That looks awfully > > strange, even if it is right.) > > it's strange because it's wrong :-) In all fairness OMAP2430 and onwards > don't really need SW to switch between host and device roles, though. > > It's only good for testing when you have the wrong cable and still want > to go to that role. That's exactly the situation I'm in (except perhaps for the testing part -- it's hard to get much information out of a commercial device). Alan Stern -- 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
