> -----Original Message----- > From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Sent: 2019年12月4日 2:15 > To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; sean@xxxxxxxxxx; > linux-can@xxxxxxxxxxxxxxx > Cc: dl-linux-imx <linux-imx@xxxxxxx>; netdev@xxxxxxxxxxxxxxx > Subject: Re: [PATCH V2 2/4] can: flexcan: try to exit stop mode during probe > stage > > On 11/27/19 6:56 AM, Joakim Zhang wrote: > > CAN controller could be stucked in stop mode once it enters stop mode > ^^^^^^^ stuck > > when suspend, and then it fails to exit stop mode when resume. > > How can this happen? I am also confused how can this happen, as I asked Sean, only CAN enter stop mode when suspend, then system hang, it could let CAN stuck in stop mode. However, Sean said this indeed happen at his side, @sean@xxxxxxxxxx, could you explain how this happen in details? > > Only code reset can get CAN out of stop mode, > > What is "code reset"? As I know, "code reset" is to press the POWER KEY from the board. At my side, reboot command from OS also can get CAN out of stop mode. Below is experiment I did: Firstly, do a hacking to let CAN stuck into stop mode, then: (1) press power on/off key, get CAN out of stop mode; (2) reboot command from console, get CAN out of stop mode; (3) unbind/bind driver, cannot get CAN out of stop mode; (4) remod/insmod module, cannot get CAN out of stop mode; > > so add stop mode remove request during probe stage for other > > methods(soft reset from chip level, unbind/bind driver, etc) to let > ^^^ please add a space > > CAN active again. > > Can you rephrase the sentence after "so add stop mode remove request during > probe stage". I'm not completely sure what you want to tell. Sure. Best Regards, Joakim Zhang > > MCR[LPMACK] will be checked when enable CAN in register_flexcandev(). > > > > Suggested-by: Sean Nyekjaer <sean@xxxxxxxxxx> > > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx> [...] > 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 |
