fix(esp_pm): update CPU frequency immediately after updating pm_config

Closes https://github.com/espressif/esp-idf/issues/13492

components/esp_pm/pm_impl.c

@@ -468,6 +468,7 @@ esp_err_t esp_pm_configure(const void* vconfig)
     s_config_changed = true;
     portEXIT_CRITICAL(&s_switch_lock);
 
+    do_switch(PM_MODE_CPU_MAX);
     return ESP_OK;
 }
 
@@ -617,7 +618,7 @@ static void IRAM_ATTR do_switch(pm_mode_t new_mode)
 #endif
         portEXIT_CRITICAL_ISR(&s_switch_lock);
     } while (true);
-    if (new_mode == s_mode) {
+    if ((new_mode == s_mode) && !s_config_changed) {
         portEXIT_CRITICAL_ISR(&s_switch_lock);
         return;
     }

components/esp_pm/test_apps/esp_pm/main/test_pm.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2024 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Unlicense OR CC0-1.0
  */
@@ -54,12 +54,8 @@ static void switch_freq(int mhz)
         .min_freq_mhz = MIN(mhz, xtal_freq_mhz),
     };
     ESP_ERROR_CHECK( esp_pm_configure(&pm_config) );
-    printf("Waiting for frequency to be set to %d MHz...\n", mhz);
-    while (esp_clk_cpu_freq() / MHZ != mhz)
-    {
-        vTaskDelay(pdMS_TO_TICKS(200));
-        printf("Frequency is %d MHz\n", esp_clk_cpu_freq() / MHZ);
-    }
+    TEST_ASSERT_EQUAL_UINT32(mhz, esp_clk_cpu_freq() / MHZ);
+    printf("Frequency is %d MHz\n", esp_clk_cpu_freq() / MHZ);
 }
 
 #if CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32C6