On 2/19/2018 9:03 PM, Marek Vasut wrote: > On 02/19/2018 11:11 AM, Minas Harutyunyan wrote: >> On 2/19/2018 12:51 PM, Marek Vasut wrote: >>> On 02/19/2018 09:19 AM, Minas Harutyunyan wrote: >>>> On 2/17/2018 12:07 AM, Marek Vasut wrote: >>>>> On 02/16/2018 06:59 AM, Minas Harutyunyan wrote: >>>>>> On 2/15/2018 5:20 PM, Mirza Krak wrote: >>>>>>> On 14 February 2018 at 13:07, Minas Harutyunyan >>>>>>> <Minas.Harutyunyan at synopsys.com> wrote: >>>>>>>> On 2/14/2018 12:57 PM, Mirza Krak wrote: >>>>>>>>> On 8 February 2018 at 14:53, Minas Harutyunyan >>>>>>>>> <Minas.Harutyunyan at synopsys.com> wrote: >>>>>>> >>>>>>> < snip > >>>>>>> >>>>>>>> >>>>>>>> I reviewed your interrupt count log again. About 140,000 interrupts in 2 >>>>>>>> seconds, obviously it's not SOF only interrupts. More probably, its NAK >>>>>>>> respond interrupts to SSPLIT/CSPLIT transactions. For this case I can >>>>>>>> recommend you to apply patch from Douglas Anderson: "[PATCH v2] usb: >>>>>>>> dwc2: host: Don't retry NAKed transactions right away" which already >>>>>>>> merged to 4.16-rc1. >>>>>>>> >>>>>>>> In your setups you see different behavior on different HUBs. Your HUBs >>>>>>>> have different "TT think time": 8 and 32. In USB2.0 spec "TT think time" >>>>>>>> described as follow "TT requires at most 8/32 FS bit times of inter >>>>>>>> transaction gap on a full-/low-speed downstream bus". So, your "worst" >>>>>>>> HUB with "TT think time"=8 sending more frequently SSPLIT/CSPLIT >>>>>>>> transactions which replied by NAK. As result you see about 4 time more >>>>>>>> interrupts comparing to "good" HUB. Could you please check interrupts >>>>>>>> count for "good" HUB and check "4 time" hypothesis. >>>>>>> >>>>>>> Did some further testing. The "good" HUB is actually as bad as the >>>>>>> "bad" HUB, and it was my setup that caused the different behavior. Did >>>>>>> not use the same devices etc. >>>>>>> >>>>>>> Once I made sure that the configuration and setup was the same on both >>>>>>> board I could see that the behaved similarly. And that is the >>>>>>> following interrupt load: >>>>>>> >>>>>>> - BT USB (FS) = ~80k interrupts / second >>>>>>> - Keyboard (FS) = ~80k interrupts / second >>>>>>> - WiFI USB (HS) = ~8k interrupts / second >>>>>>> >>>>>>> After applying the suggested patch [1], it is steady around 8k >>>>>>> interrupts / second no matter what device I connect (HS/FS, >>>>>>> HUB/NO-HUB). Which is acceptable and usable. >>>>>> >>>>>> Great! >>>>> >>>>> So 8k IRQs per second is what I should expect from this HW with HS >>>>> device attached, that's normal and cannot be reduced ? >>>>> >>>> If core acting as Host in Buffer DMA mode then 8k IRQs per second (SOF >>>> interrupts) is expected if connected device(s) has periodic endpoint. >>> >>> Is there a way to reduce that or is that the absolute minimum in HS mode? >>> >> We already discussed, in this email thread earlier, why SOF interrupts >> required and unmasked. >> Only in case when connected device with CTRL+BLK EP's only (like flash >> drive) and directly connected to cores root HUB, SOF's will be masked. > > That's the setup I have on Altera SoCFPGA, yet the SOFs are still present. > Could you please send verbose lsusb on connected to dwc2 device and driver debug log. Thanks, Minas
