Felipe, On Tue, Oct 25, 2016 at 08:57:26AM -0500, Bin Liu wrote: > On Tue, Oct 25, 2016 at 04:44:13PM +0300, Felipe Balbi wrote: > > [snip] > > > > Just reviewed this patch, it seems to be the regression. But SS should > > > not generate ID pin event either, right? SS uses far-end termination, it > > > does not have ID pin as USB2.0. I will try to revert this patch to find > > > out... > > > > it's not about speed :-) ID pin is used nevertheless to choose role, but > > Yeah, you are right. I messed it up with type-C, somehow thought ID pin > is not required for SS :-( > > > some TI boards didn't provide any methods for VBUS sampling, so ID pin > > was used to tell DWC3 if it should be host/device AND if VBUS_VALID or > > not. > > > > Note that we end up lying to the controller because we could set > > VBUS_VALID before VBUS really is valid, but it's better than never > > seeing a connection at all ;-) > > Make more sense now :-) I will play with the patch mentioned, and ensure > any future boards have vbus sampling so we can decouple it with ID pin > events in the UTMI mailbox. > > Still need to figure out why highspeed is not affected... Ok, I think I understand most part of the problems now. VBUS detect is required for disconnect event, so AM57x board design should have a GPIO for VBUS detect to feed to extcon. 1. why only SS is affected on dra7-evm? This is because of USB3.0 LPM. With g_zero, dwc3 SS in device mode goes to U2 after been enumerated, in which state dwc3 is unable to detect any change other than link change. But dwc3 HS stays in U0 after been enumerated, so the link goes to RX.Detect after detach from the host. So dwc3 HS can still detect the connect to host even with lack of disconnect interrupt. 2. why dra7-evm used to work? Very likely the kernel at that time does not support LPM, so dwc3 SS is still in U0 after been enumerated, the same case as in HS above. At least this is what I see with kernel 3.14, in which dwc3 SS doesn't go to U2. Thanks for helping me understanding this. I will ensure any future board design will have VBUS detect. Regards, -Bin. -- 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
