"ext Rajendra Nayak" <rnayak@xxxxxx> writes: >> -----Original Message----- >> From: "Högander" Jouni [mailto:jouni.hogander@xxxxxxxxx] >> Sent: Wednesday, July 09, 2008 12:29 PM >> To: ext Rajendra Nayak >> Cc: linux-omap@xxxxxxxxxxxxxxx >> Subject: Re: [PATCH] OMAP3: CPUIDLE & PM: check_bm fix. >> >> "ext Rajendra Nayak" <rnayak@xxxxxx> writes: >> >> > >> >> -----Original Message----- >> >> From: Jouni Hogander [mailto:jouni.hogander@xxxxxxxxx] >> >> Sent: Wednesday, July 09, 2008 12:00 PM >> >> To: linux-omap@xxxxxxxxxxxxxxx; rnayak@xxxxxx >> >> Subject: [PATCH] OMAP3: CPUIDLE & PM: check_bm fix. >> >> >> >> This patch fixes problems with uart usage. omap3_enter_idle_bm was >> >> select C5 and C6 states even if there was "bus activity. >> > >> > Am not very clear on what was the issue with the previous >> logic that it would >> > attempt a C5/C6 even with bus activity. >> >> If you try it you will notice the difference;) What is the meaning of >> this bm check if C5/C6 is used even when there is >> "acitivity". > > No, What I meant to say was that the previous logic I thought was good enough to > *prevent* C5/C6 or any other state with CPUIDLE_FLAG_CHECK_BM flag set, while there is > bus activity and then go ahead and select the highest possible state with > CPUIDLE_FLAG_CHECK_BM _not_ set. Yes you are right. Current implementation is ok, maybe this change?: diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx.c index c14152f..7c97c7d 100644 --- a/arch/arm/mach-omap2/cpuidle34xx.c +++ b/arch/arm/mach-omap2/cpuidle34xx.c @@ -484,7 +484,7 @@ static int omap3_enter_idle_bm(struct cpuidle_device *dev, BUG_ON(i == OMAP3_MAX_STATES); /* Back up to non 'CHECK_BM' state */ - for (j = i - 1; j > 0; j--) { + for (j = i - 1; j >= 0; j--) { struct cpuidle_state *s = &dev->states[j]; if (!(s->flags & CPUIDLE_FLAG_CHECK_BM)) { This caused my misunderstanding. I tried to mark all states except C0 with bm check flag and omap3_enter_idle_bm was selecting C6 even when there was "activity". Anyway serial console seems to work very slow if mpu is entering wfi. This can be checked by marking C1 and C2 with bm check flag. > > Anyway if >> you want to have bm check code in your cpuidle driver you need to >> rewrite the check code. I have seen that omap3_can_sleep partially as >> a workaround. Just to make sure PM doesn't break any driver as long as >> they are not all configured properly what comes to interconnect. Just >> like what happened here as cpuidle was trying to enter C5/C6. >> >> > >> >> >> >> Signed-off-by: Jouni Hogander <jouni.hogander@xxxxxxxxx> >> >> --- >> >> arch/arm/mach-omap2/cpuidle34xx.c | 23 +++++++---------------- >> >> arch/arm/mach-omap2/pm34xx.c | 2 +- >> >> 2 files changed, 8 insertions(+), 17 deletions(-) >> >> >> >> diff --git a/arch/arm/mach-omap2/cpuidle34xx.c >> >> b/arch/arm/mach-omap2/cpuidle34xx.c >> >> index c14152f..a636edb 100644 >> >> --- a/arch/arm/mach-omap2/cpuidle34xx.c >> >> +++ b/arch/arm/mach-omap2/cpuidle34xx.c >> >> @@ -473,31 +473,22 @@ static int omap3_enter_idle_bm(struct >> >> cpuidle_device *dev, >> >> struct cpuidle_state *state) >> >> { >> >> struct cpuidle_state *new_state = NULL; >> >> - int i, j; >> >> - >> >> - if ((state->flags & CPUIDLE_FLAG_CHECK_BM) && >> >> omap3_idle_bm_check()) { >> >> - >> >> - /* Find current state in list */ >> >> - for (i = 0; i < OMAP3_MAX_STATES; i++) >> >> - if (state == &dev->states[i]) >> >> - break; >> >> - BUG_ON(i == OMAP3_MAX_STATES); >> >> - >> >> - /* Back up to non 'CHECK_BM' state */ >> >> - for (j = i - 1; j > 0; j--) { >> >> - struct cpuidle_state *s = &dev->states[j]; >> >> + int i; >> >> >> >> + if (omap3_idle_bm_check()) { >> >> + for (i = 0; i < OMAP3_MAX_STATES; i++) { >> >> + struct cpuidle_state *s = &dev->states[i]; >> > >> > So now a C0 is attempted every time there is bus activity? >> >> Yes you are right here. This code is not very effective. It should >> select deepest sleep state without CPUIDLE_FLAG_CHECK_BM. >> >> > >> >> if (!(s->flags & CPUIDLE_FLAG_CHECK_BM)) { >> >> new_state = s; >> >> break; >> >> } >> >> } >> >> - >> >> + BUG_ON(i == OMAP3_MAX_STATES); >> >> pr_debug("%s: Bus activity: Entering %s >> >> (instead of %s)\n", >> >> - __FUNCTION__, new_state->name, state->name); >> >> + __FUNCTION__, new_state->name, state->name); >> >> } >> >> >> >> - return omap3_enter_idle(dev, new_state ? : state); >> >> + return omap3_enter_idle(dev, new_state ? new_state : state); >> >> } >> >> >> >> DEFINE_PER_CPU(struct cpuidle_device, omap3_idle_dev); >> >> diff --git a/arch/arm/mach-omap2/pm34xx.c >> >> b/arch/arm/mach-omap2/pm34xx.c >> >> index 9f73e5c..ca0600a 100644 >> >> --- a/arch/arm/mach-omap2/pm34xx.c >> >> +++ b/arch/arm/mach-omap2/pm34xx.c >> >> @@ -734,7 +734,7 @@ static int __init pwrdms_setup(struct >> >> powerdomain *pwrdm) >> >> pwrdm_enable_hdwr_sar(pwrdm); >> >> >> >> if (!strcmp(pwrst->pwrdm->name, "core_pwrdm") || >> >> !strcmp(pwrst->pwrdm->name, "mpu_pwrdm") || >> >> - !strcmp(pwrst->pwrdm->name, "mpu_pwrdm")) >> >> + !strcmp(pwrst->pwrdm->name, "neon_pwrdm")) >> >> return set_pwrdm_state(pwrst->pwrdm, PWRDM_POWER_ON); >> >> else >> >> return set_pwrdm_state(pwrst->pwrdm, pwrst->next_state); >> >> -- >> >> 1.5.5 >> >> >> >> >> > >> > >> > >> >> -- >> Jouni Högander >> >> > > -- > 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 > > -- Jouni Högander -- 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
