From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Fri, 21 Jun 2013 15:22:35 +0200 Subject: [PATCH] at91: cpuidle: Fix target_residency In-Reply-To: <51C45320.8090102@atmel.com> References: <1371818219-13060-1-git-send-email-daniel.lezcano@linaro.org> <51C45320.8090102@atmel.com> Message-ID: <51C4539B.3020506@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 06/21/2013 03:20 PM, Nicolas Ferre wrote: > On 21/06/2013 14:36, Daniel Lezcano : >> The following commit: >> >> commit 7e348b9012522fa0efd854d20d210d5e57fcedd1 >> Author: Robert Lee >> Date: Tue Mar 20 15:22:43 2012 -0500 >> >> ARM: at91: Consolidate time keeping and irq enable >> >> Enable core cpuidle timekeeping and irq enabling and remove that >> handling from this code. >> >> introduced a zero to the state1 (suspend) target residency. >> >> [ ... ] >> >> + .states[1] = { >> + .enter = at91_enter_idle, >> + .exit_latency = 10, >> + .target_residency = 100000, >> + .flags = CPUIDLE_FLAG_TIME_VALID, >> + .name = "RAM_SR", >> + .desc = "WFI and DDR Self Refresh", >> + }, >> >> [ ... ] >> >> - /* Wait for interrupt and RAM self refresh state */ >> - driver->states[1].enter = at91_enter_idle; >> - driver->states[1].exit_latency = 10; >> - driver->states[1].target_residency = 10000; >> - driver->states[1].flags = CPUIDLE_FLAG_TIME_VALID; >> - strcpy(driver->states[1].name, "RAM_SR"); >> - strcpy(driver->states[1].desc, "WFI and RAM Self Refresh"); >> >> [ ... ] >> >> The cpuidle never enters this state since this commit. To be a bit more precise. With a periodic tick, the cpu never enters the state1 with both 10000 and 100000. With a tickless system, it enters to state1 much more often with the initial value, roughly x7 more. BTW, I am surpised with a sam926*, CONFIG_NO_HZ=y is not in the default config. >> Fix it by setting the value to 10ms again. >> >> Signed-off-by: Daniel Lezcano > > Acked-by: Nicolas Ferre > >> --- >> arch/arm/mach-at91/cpuidle.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm/mach-at91/cpuidle.c b/arch/arm/mach-at91/cpuidle.c >> index 69f9e3b..4ec6a6d 100644 >> --- a/arch/arm/mach-at91/cpuidle.c >> +++ b/arch/arm/mach-at91/cpuidle.c >> @@ -51,7 +51,7 @@ static struct cpuidle_driver at91_idle_driver = { >> .states[1] = { >> .enter = at91_enter_idle, >> .exit_latency = 10, >> - .target_residency = 100000, >> + .target_residency = 10000, >> .flags = CPUIDLE_FLAG_TIME_VALID, >> .name = "RAM_SR", >> .desc = "WFI and DDR Self Refresh", >> > > -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog