Hi Sebastian, On 25/03/2015 13:15, Sebastian Andrzej Siewior wrote:
>> >> Just some questions. The described behavior is coherent with the >> description in the manual. When WDW is set, the watchdog is stopped >> while the processor is in wait mode. > > I fail to notice how it could make any sense. Well, I have not said it makes sense - only that the behavior is expected ;-) > >> Current imx2_wdt.c driver in kernel does not care about this bit, but it >> looks like that only the kernel and/or the application can decide if the >> watchdog should run when the system is in WAIT or not. The bootloader >> cannot decide, and it should set the bit for its own usage. >> >> Should this setup be done by the kernel driver instead of by the >> bootloader ? > > It is a one-time-bit. Once it is set (or not) it can not be changed > later. It makes no difference for the bootloader. mmhhh..Sorry, it looks like I read the wrong line in the manual. This is a write once bit exactly as WDZST. My assumption were wrong. We cannot disable in kernel if the bootloader has already activated it. > And the kernel may > remain idle for longer than one jiffy with NO_HZ but it will still wake > up within a second if I remember correctly. Eitherway the user will > usually trigger the WD in timeout/2 so atleast that timer will wake up > the kernel from idle. > Having the WDT not account the idle time makes it hard for the user to > figure out how much time has been accounted by the WDT so far. I have no objections here - I start from the wrong assumption that the bit could be cleared by the kernel, but it is not. > >>> >>> While I don't see a reason why the WDT should not be running while the >>> CPU is in idle, I'm dropping this bit. >> >> I can agree or disagree. This depends on the application. >> >> Differently as the WDZST, that can be set only once, and it is set by >> *both* U-Boot and kernel (setting in kernel has then no influence), the >> WDW can be even disabled in kernel. > > I patched the kernel as well. Once I get through here I would also push > patches there. The thing I don't like is that the kernel pings the WDT > on its own. While it may make sense for some people I would like to > atleast configure it :) Agree, patch put in my merge queue. Acked-by: Stefano Babic <sba...@denx.de> Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
