"Premi, Sanjeev" <premi@xxxxxx> writes: >> -----Original Message----- >> From: Högander Jouni [mailto:jouni.hogander@xxxxxxxxx] >> Sent: Monday, March 09, 2009 3:36 PM >> To: Premi, Sanjeev >> Cc: linux-omap@xxxxxxxxxxxxxxx >> Subject: Re: Problems in cpuidle >> >> "ext Premi, Sanjeev" <premi@xxxxxx> writes: >> >> > While working with cpuidle, I have come across these problems. >> > I am also working on the solutions, but would be good to hear more >> > thoughts. >> > >> > 1) The flag 'enable_dyn_sleep' is honoured only in >> omap3_idle_bm_check() >> > but in the C1 state, omap3_enter_idle() is invoked directly. >> > So, the system can transition to deeper idle state(s) >> > >> > Same is the case with 'sleep_block'. >> > >> > Possible Solutions: >> > a) Call omap3_can_sleep() in omap3_enter_idle(). >> > This makes omap3_idle_bm_check() redundant; and >> can be removed. >> > >> > b) Make single entry point for all idle states >> > But would be an overkill for C1 state. >> > >> > c) Change omap3_can_sleep() to check for omap_uart_can_sleep() >> > and omap3_fclks_active() only. >> > Move check for 'enable_dyn_sleep' and 'sleep_block' into >> > omap3_enter_idle() >> > >> > I believe (c) would be the most optimal. >> >> Selecting (c) will break traditional pm_idle. Current plan is >> to add one more C state (C1) which would prevent mpu/core >> sleep transitions. Then remove fclk_active check completely. > > [sp] I meant doing the same for pm_idle as well. > Also, the new cstate will not help with 'sleep' block. > > The proposed change look like: > > diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx > index 7fc3cb3..c25158c 100644 > --- a/arch/arm/mach-omap2/cpuidle34xx.c > +++ b/arch/arm/mach-omap2/cpuidle34xx.c > @@ -82,6 +82,11 @@ static int omap3_enter_idle(struct cpuidle_device *dev, > /* Used to keep track of the total time in idle */ > getnstimeofday(&ts_preidle); > > + if (!enable_dyn_sleep) > + goto return_sleep_time; > + if (atomic_read(&sleep_block) > 0) > + goto return_sleep_time; > + > /* > * Adjust the idle state (if required). > * Also, ensure that usage statistics of correct state are updated. > diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c > index 0716d60..5c7819a 100644 > --- a/arch/arm/mach-omap2/pm34xx.c > +++ b/arch/arm/mach-omap2/pm34xx.c > @@ -476,14 +476,10 @@ static int omap3_fclks_active(void) > > int omap3_can_sleep(void) > { > - if (!enable_dyn_sleep) > - return 0; > if (!omap_uart_can_sleep()) > return 0; > if (omap3_fclks_active()) > return 0; > - if (atomic_read(&sleep_block) > 0) > - return 0; > return 1; > } > > @@ -534,6 +530,11 @@ err: > > static void omap3_pm_idle(void) > { > + if (!enable_dyn_sleep) > + return; > + if (atomic_read(&sleep_block) > 0) > + return; > + > local_irq_disable(); > local_fiq_disable(); > Sanjeev, I think it's cleaner to just make all the states go through the 'bm_check', so the standard PM idle and CPUidle use the same paths. 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
