hi,
Anurag Kumar Vulisha <anura...@xilinx.com> writes: >>Does the data book suggest a value for the timeout? >> > > No, the databook doesn't mention about the timeout value > >>> >At this point, it seems that the generic approach will be messier than >>> >having every >>> >controller driver implement its own fix. At least, that's how it appears >>> >to me. Why, if the UDC implementation will, anyway, be a timer? >>(Especially if dwc3 is the only driver affected.) > > As discussed above, the issue may happen with other gadgets too. As I got > divide opinions > on this implementation and both the implementations looks fine to me, I am > little confused > on which should be implemented. > > @Felipe: Do you agree with Alan's implementation? Please let us know your > suggestion > on this. I still think a generic timer is a better solution since it has other uses. >>> >Ideally it would not be necessary to rely on a timeout at all. >>> > >>> >Also, maintainers dislike module parameters. It would be better not to >>> >add one. >>> >>> Okay. I would be happy if any alternative for this issue is present but >>> unfortunately >>> I am not able to figure out any alternative other than timers. If not >>module_params() >>> we can add an configfs entry in stream gadget to update the timeout. Please >>provide >>> your opinion on this approach. >> >>Since the purpose of the timeout is to detect a deadlock caused by a >>hardware bug, I suggest a fixed and relatively short timeout value such >>as one second. Cancelling and requeuing a few requests at 1-second >>intervals shouldn't add very much overhead. I wouldn't call this a HW bug though. This is just how the UDC behaves. There are N streams and host can move data in any stream at any time. This means that host & gadget _can_ disagree on what stream to start next. One way to avoid this would be to never pre-start any streams and always rely on XferNotReady, but that would mean greatly reduced throughput for streams. -- balbi
