On Tue, 9 Apr 2019 09:28:16 +0000 Minas Harutyunyan wrote: > > Hi Stefan, > > > Hi Minas, > > > > Am 09.04.19 um 08:54 schrieb Jisheng Zhang: > >> On Mon, 8 Apr 2019 16:05:51 +0800 Jisheng Zhang wrote: > >> > >>> Hi Stefan, > >>> > >>> On Mon, 8 Apr 2019 09:57:14 +0200 Stefan Wahren wrote: > >>> > >>>> > >>>> Hi Jisheng, > >>>> > >>>> > >>>> thanks for sending this patch. I already reported this issue > >>>> last year [1], but Microchip wasn't able to provide a fix. > >>>> > >>>> I will give it a try. > >>>> > >>>>> The second one: 8000 usb interrupts per second when idle. > >>>>> This is abnormal. any idea? Is it due to the lan78xx? > >>>> Does this downstream patch [2] improve your situation? > >>> Thanks a lot. Will try the patch tonight. > >> I tried this patch, it doesn't help. One more observation: if I > >> ifconfig eth0 down, I can still get 8000 usb interrupts per second. > >> Not sure whether this is usb issue or not. > > > > Jisheng reports a lot of USB interrupts while the lan78xx driver on > > Raspberry Pi 3B+ is in idle. > > > > Any suggestions to narrow this down? > > dwc2 in host mode enable SOF interrupts if any periodic EP are in use. > So, 8000 interrupts per second is expectant behavior. Makes sense. 8 microframes each 1ms, so 8*1000 = 8000 interrupts/s
