Messages in this thread | | | Date | Thu, 15 Aug 2013 00:59:29 +0100 | From | Mark Brown <> | Subject | Re: Non-enumerable devices on USB and other enumerable buses |
| |
On Wed, Aug 14, 2013 at 08:16:56PM +0000, Paul Zimmerman wrote:
> Mark's original complaint about USB was this: > > > the device). The hub needs to be "plugged" into the SoC after the SoC > > USB controller has started with some GPIOs so we need to tell the system > > that the hub exists and needs to be synchronised with the USB controller.
> This sounds to me like the normal discovery mechanism for USB isn't getting > kicked off because no Connect Status Change is being triggered on the root > port when the hub is brought online using the GPIOs. Maybe the port has > been runtime suspended because no device was attached originally?
> So maybe the only thing needed for USB is a way to tell the parent port to > frob its port control bits to try to determine if a device is now present. > (set Wake on Connect Enable? Do a Port Reset? Cycle the Port Power bit if > possible?)
No, that's not required in this case - the case is the opposite one to the one you describe. Host starting first then hub works fine, if the host does go into a low power mode it seems to notice the hub appearing just fine. Hub then host fails for some reason which I don't know. [unhandled content-type:application/pgp-signature] | |