On Fri, 2024-11-01 at 14:21 -0400, Patrick Williams wrote: > On Fri, Nov 01, 2024 at 08:11:59PM +0800, Chin-Ting Kuo wrote: > > The boot status mapping rule follows the latest design guide from > > the OpenBMC shown as below. > > https://github.com/openbmc/docs/blob/master/designs/bmc-reboot-cause-update.md#proposed-design > > - WDIOF_EXTERN1 => system is reset by Software > > - WDIOF_CARDRESET => system is reset by WDT SoC reset > > - Others => other reset events, e.g., power on reset. > > I'm quite surprised that the above is relevant for a kernel driver at > all. Isn't "EXTERN1" a name of a real watchdog signal from your > hardware (my recollection is that there are 2 external watchdogs). I think you may be referring to WDTRST1 (and WDTRST2) here. WDIOF_EXTERN1 and WDIOF_EXTERN2 have an unrelated history: https://github.com/torvalds/linux/blame/master/include/uapi/linux/watchdog.h > I > think the point of this referenced design document was that most > users > of BMCs have "EXTERN1" used a for software reset conditions. > `CARDRESET` should be representing resets by the watchdog itself. I think this is what Chin-Ting is proposing for the Aspeed driver? > > The purpose of this design proposal was not to require very specific > changes to individual watchdog drivers, but to align the userspace > use > with the best practices already from other watchdog drivers. I don't > think the kernel driver should be bending to match a particular > userspace implementation; you should be exposing the information > available to your hardware. I agree with this in principle, but I'm not sure what else is meant to be done here. > > Having said that, it was known that there would need to be changes to > the driver because some of these conditions were not adequately > exposed > at all. I'm just still surprised that we're needing to reference > that > document as part of these changes. I think the main question is whether an internal, graceful (userspace- requested) reset is a reasonable use of WDIOF_EXTERN[12]. My feeling no. I wonder whether defining a new flag (WDIOF_REBOOT? WDIOF_GRACEFUL?) in the UAPI would be acceptable? Andrew
