"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) Kevin -- 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
