On 11/13/2015 06:39 PM, santosh shilimkar wrote: > On 11/13/2015 5:07 AM, Mason wrote: >> On 13/11/2015 13:48, Grygorii Strashko wrote: >>> On 11/12/2015 08:06 PM, Felipe Balbi wrote: >>>> Make sure to tell the kernel that AM437x has >>>> TWD and global timers. >>>> >>>> Signed-off-by: Felipe Balbi <balbi@xxxxxx> >>>> --- >>>> >>>> Hi Tony, >>>> >>>> now that all dependencies are in place, we can >>>> finally enable twd and global_timer for AM437x. >>>> > Is AM437x SMP SOC ? No. But it has ARM TWD and GT > Is TWD on AM437x works in low power states ? No. But TWD, seems, is not a problem here if omap gp timer can be used as broadcast device. > Probably I haven't followed the recent updates, but does > the TWD supports C3STOP on UP systems ? The broadcast > code was SMP only in past, and TWD use to die in > low power state on past OMAP SOCs. > > If either of these are still the issue then > TWD shouldn't be used. > Yep. I see the problem with ARM Global timer here if CPUIdle is enabled and ARM Global timer is selected as clocksource device. I think, it will be right thing to disable "global_timer" and "local_timer" nodes in am437x.dtsi by default - if someone would like to use them then those nodes have to be enabled explicitly in board file. (TWD timer will be enabled on OMAP multi SoC build irrespectively of HAVE_ARM_TWD is selected for am437x or not, because it will be selected for omap4). I've just sent corresponding patch: http://www.spinics.net/lists/arm-kernel/msg461141.html Also, probably, it could be reasonable to: - make ARM_GLOBAL_TIMER fully selectable option and allow select it from defconfig. - or - update this patch as below - select ARM_GLOBAL_TIMER - select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK + select ARM_GLOBAL_TIMER if !CPU_IDLE + select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK if ARM_GLOBAL_TIMER Thanks. -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
