> -----Original Message----- > From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Sent: 2019年11月12日 19:04 > To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; sean@xxxxxxxxxx; > linux-can@xxxxxxxxxxxxxxx > Subject: Re: Wake up issue about Flexcan driver in v5.4 kernel > > On 11/12/19 11:47 AM, Joakim Zhang wrote: > >> I think we can explain case 2), but I think case 1) is different. Can > >> you repeat testcase 1) several times and send the output? > > > > I do not quite understand. Bus bitrate 1Mbps, so the counter overrun every > 65ms: > > Case 1) default frame gap is 200ms, case 2) configured frame gap > > 100ms, why we can explain case 2)? What is the essence of these two? > > Oh, I missed the fact that 1) uses the default gap of 200ms. > > The problem is wakeup latency from frame reception to IRQ handler is much > bigger than the counter overflow. > > Then we can explain cases 1) and 2). > > The question remains, has the wakeup time increased compared to older > kernels? Or was it pure luck that you have not seen this problem in older > kernels? I have tested all upstream version since stop mode enabled(v5.1, v5.2, v5.3, v5.4), this issue all exist. With our local 4.14 and 4.19, it is fine, maybe we optimize suspend/resume at local. Best Regards, Joakim Zhang > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | https://www.pengutronix.de | > Vertretung West/Dortmund | Phone: +49-231-2826-924 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
