On Mon, Apr 30, 2012 at 03:00:56PM -0700, Kevin Hilman wrote: > "Mark A. Greer" <mgreer@xxxxxxxxxxxxxxx> writes: > > > On Fri, Apr 27, 2012 at 02:12:12PM -0700, Kevin Hilman wrote: > >> "Mark A. Greer" <mgreer@xxxxxxxxxxxxxxx> writes: > >> > >> > On Tue, Apr 24, 2012 at 01:51:05PM -0700, Mark A. Greer wrote: > > > >> > Just thinking out loud... > >> > > >> > We could chose whether pm_idle & cpuidle issue a wfi based on > >> > whether there is a davinci-emac present. The issue with that is > >> > that someday there may be another SoC that has a davinci-emac that > >> > can wake up the system. I know cpu_is_xxx() is frowned upon but > >> > this does seem like a proper usage of it--the deciding factor > >> > really is whether its an am35x or not (and CONFIG_TI_DAVINCI_EMAC > >> > is enabled). > >> > >> The presence of the davinci_emac is probably overkill, avoiding WFI > >> should really only be done when the davinci_emac is *active*. > >> e.g. using an am35x with an EMAC *present*, but not in use because > >> there's an MMC rootfs for example. > >> > >> If there's a good way to detect an in-use davinci_emac, then > >> disable_hlt() can be used to avoid WFI. When the davinci_emac is not in > >> use (e.g. module unloaded etc.) then enable_hlt() can be used to > >> (re)allow WFI. > > > > This can work for pm_idle but what should be done for cpu_idle > > (as in, omap3_enter_idle[_bm])? We should have some sort of > > solution for that so users can safely enable CONFIG_CPU_IDLE > > and not have the am3517 fall apart. > > disable_hlt() will prevent either the default idle *or* CPUidle from > being called. > > It will simply call cpu_relax() instead of calling any idle > function. (c.f. cpu_idle() in arch/arm/kernel/process.c) Yep, you're right. Sorry. Mark -- 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
