> -----Original Message----- > From: Alexandre Belloni <alexandre.bell...@bootlin.com> > Sent: Friday, June 14, 2019 4:33 PM > To: Ken Sloat <ksl...@aampglobal.com> > Cc: Guenter Roeck <li...@roeck-us.net>; nicolas.fe...@microchip.com; > ludovic.desroc...@microchip.com; w...@linux-watchdog.org; linux-arm- > ker...@lists.infradead.org; linux-watch...@vger.kernel.org; linux- > ker...@vger.kernel.org > Subject: Re: [PATCH v2 1/1] watchdog: atmel: atmel-sama5d4-wdt: Disable > watchdog on system suspend > > [This is an EXTERNAL EMAIL] > ________________________________ > > On 14/06/2019 18:43:22+0000, Ken Sloat wrote: > > Well I'm a little confused still because there are two separate > > comments in these statements. The first within resume implies that the > > init should be called because we might have lost register values for > > some reason unexplained. > > The sama5d2 has a suspend mode where power to the core is completely > cut. Only a few IPs remain powered (in the backup power domain). > Unfortunately, the watchdog is not in that domain and may lose its registers. > > > Then within the init it says that the bootloader might have modified > > the registers so we should check them and then update it or otherwise > > disable it. I'm not trying to pick apart the logic or anything, I'm > > just readily assuming it is good as it was already reviewed before. > > > > The bootloaders may have started the watchdog (this makes sense if you > really care about reliability) and so we need to be careful to keep the proper > parameters.
Thanks for the explanation Alexandre I appreciate it. > > So without digging into that too much, if we don't know if any of the > > runtime situations above might have occurred, then isn't it best to > > leave my patch as is? Yes this has the side effect of resetting the > > timer count, but if the init call is needed and we don't have any way > > to know if any of the situations occurred, then we have no choice right? > > > > Until we can differentiate between suspend modes, we have no other > choice. Ok I will leave my patch as is for now then > -- > Alexandre Belloni, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com Thanks, Ken Sloat
