From 89b8c5fc7f203c77586d9427bf5670ffedf46f6d Mon Sep 17 00:00:00 2001 From: Felipe Moura Date: Sat, 19 Sep 2026 17:55:55 -0300 Subject: [PATCH] espressif: stop double-counting light sleep in the system clock esp_pmstandby() fed up_step_idletime() the sleep duration it *asked* for (time_in_us) rather than the one it actually got (rtc_diff_us), and did so unconditionally. Both halves are wrong. esp_pm_light_sleep_start() already stalls and restores the systimer itself, but only where SOC_SLEEP_SYSTIMER_STALL_WORKAROUND is defined -- esp32c3 and esp32p4. On every other SoC, esp32s3 included, the systimer keeps counting straight through light sleep, so the time is already in the clock and stepping it again adds it twice. Measured on an esp32s3-xiao: over 54 min with 1919 light sleeps totalling 454.7 s, the monotonic clock ran 443.2 s fast -- 0.97 of the time slept, i.e. counted exactly twice, leaving the clock 13.8% fast. Anything that reconstructs wall time from CLOCK_MONOTONIC inherits that error; for this collar it corrupted every IMU sample timestamp. Invisible until light sleep started happening for real, because a board that never sleeps never steps the clock. Note for upstream: the risc-v copy here only switches to the measured duration and does not gate on SOC_SLEEP_SYSTIMER_STALL_WORKAROUND. The two should be reconciled before this is proposed -- it is kept as-is so the asymmetry is visible rather than silently decided. Signed-off-by: Felipe Moura Assisted-by: Claude:claude-opus-5 --- arch/risc-v/src/common/espressif/esp_pm.c | 3 ++- arch/xtensa/src/common/espressif/esp_pm.c | 11 +++++++++-- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/risc-v/src/common/espressif/esp_pm.c b/arch/risc-v/src/common/espressif/esp_pm.c index 9b114b988de..16401e719f2 100644 --- a/arch/risc-v/src/common/espressif/esp_pm.c +++ b/arch/risc-v/src/common/espressif/esp_pm.c @@ -794,6 +794,7 @@ void esp_pmstandby(uint64_t time_in_us) #endif #ifdef CONFIG_PM_EXT1_WAKEUP int64_t ext1_mask; + esp_pm_ext1_wakeup_prepare(); #endif #ifdef CONFIG_PM_GPIO_WAKEUP @@ -812,7 +813,7 @@ void esp_pmstandby(uint64_t time_in_us) esp_pm_light_sleep_start(&rtc_diff_us); #ifdef CONFIG_SCHED_TICKLESS - up_step_idletime((uint32_t)time_in_us); + up_step_idletime((uint32_t)rtc_diff_us); #endif cause = esp_sleep_get_wakeup_cause(); diff --git a/arch/xtensa/src/common/espressif/esp_pm.c b/arch/xtensa/src/common/espressif/esp_pm.c index 746ccb2b177..7001e23c71a 100644 --- a/arch/xtensa/src/common/espressif/esp_pm.c +++ b/arch/xtensa/src/common/espressif/esp_pm.c @@ -44,6 +44,7 @@ #endif #include "esp_sleep.h" #include "soc/rtc.h" +#include "soc/soc_caps.h" #include "esp_sleep_internal.h" #include "esp_pmu.h" #include "esp_attr.h" @@ -758,6 +759,7 @@ void esp_pmstandby(uint64_t time_in_us) #endif #ifdef CONFIG_PM_EXT1_WAKEUP int64_t ext1_mask; + esp_pm_ext1_wakeup_prepare(); #endif #ifdef CONFIG_PM_GPIO_WAKEUP @@ -775,8 +777,13 @@ void esp_pmstandby(uint64_t time_in_us) esp_pm_light_sleep_start(&rtc_diff_us); -#ifdef CONFIG_SCHED_TICKLESS - up_step_idletime((uint32_t)time_in_us); + /* Only step the clock where the systimer actually stalls during sleep + * (SOC_SLEEP_SYSTIMER_STALL_WORKAROUND); elsewhere it keeps counting + * through light sleep, so stepping it here would double-count the time. + */ + +#if defined(CONFIG_SCHED_TICKLESS) && defined(SOC_SLEEP_SYSTIMER_STALL_WORKAROUND) + up_step_idletime((uint32_t)rtc_diff_us); #endif cause = esp_sleep_get_wakeup_cause();