Hi, Rob Weber <rob@xxxxxxxxxxx> writes: >> > If not, is there some mechanism we could implement to reset the >> > dwc3 when we enter compliance mode? I attempted some sort of mechanism >> > to reset the link state, but it does not seem to help the issue. I've >> > attached my patch and the trace events for my attempted workaround to >> > this email. My initial approach was to transition the link from >> > Compliance -> SS.Disabled -> Rx.Detect when we detect we've entered >> > compliance mode. The traces show that the dwc3 just enters LFPS.Polling >> > and subsequently enters compliance mode, despite the link being reset. >> >> I think you would have to go through the entire Power On Reset >> sequence, but that's likely to be flakey. > > Okay, good to know. I am not confident in this approach as well because of > the state management / recovery we might have to perform. > > I wanted to explain our goal a little bit more in depth in case some > other apprach might come to mind. Our product supports 3 ways in which > the user can work with the USB port: Host mode, Mass Storage Mode, and > Ethernet Mode. Host mode is pretty straightforward. Users will generally > work with USB mass storage devices and USB-Ethernet adapters in host > mode. Mass storage mode exposes an internal user data partition using > f_mass_storage and configfs so the user can connect our product to their > host computer for backing up data. Ethernet uses the f_ecm and f_rndis > functions creating an ethernet connection with USB hosts, particularly > mobile devices, to interact with our mobile applications and servers > through a wired connection. > > We control this functionality through a userspace application written in Go > that creates the gadget/function configuration in configfs. Given this > background information, are there any approaches that come to mind, such > as reconfiguring the gadget? Thanks in advance for your input. Not really, if it goes into compliance mode, the only way to get it out of there is with a power-on reset. You can't even change link state back to U0 as that will just tell dwc3 to walk through the compliance patterns :-p I think our best bet is understanding why we're transitioning to compliance and preventing that. One question comes to mind: Does this happen *only* with the ethernet gadget? Does it happen with *all* hosts or just a particular host? Any chance you can capture a full session with both CATC or Beagle 5000 analyzer and dwc3 tracepoints and send it to me? >> > <idle>-0 [003] dNs2 184.588232: dwc3_core: Compliance Mode detected. Attempting recovery routine >> >> Don't we get an interrupt for Compliance mode entry? > > Not that I've seen, surprisingly. My compliance mode recovery mechanism > looks for both compliance mode and loopback mode, neither of which I > have ever seen in the link state change events. That's odd, I would expect it to still give the event. Oh well, moving on :-) -- balbi
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