applications: nrf_desktop: Use USB SOF synchronization on nRF54H

This is done to improve HID report rate stability.

Jira: NCSDK-30503

Signed-off-by: Marek Pieta <Marek.Pieta@nordicsemi.no>
Signed-off-by: Pekka Niskanen <pekka.niskanen@nordicsemi.no>

Author: MarekPieta

applications/nrf_desktop/doc/usb_state.rst

@@ -85,6 +85,9 @@ The module informs that the HID report was sent using :c:struct:`hid_report_sent
   In the case of :ref:`nrf_desktop_hid_mouse_report_handling`, enabling the USB SOF synchronization also synchronizes motion sensor sampling with the USB SOF instead of USB polls (motion sensor sampling is synchronized to :c:struct:`hid_report_sent_event`).
   This synchronization ensures that the sensor is sampled more evenly.
 
+The :ref:`CONFIG_DESKTOP_USB_HID_REPORT_SENT_ON_SOF <config_desktop_app_options>` Kconfig option is enabled by default on the nRF54H Series SoC (:kconfig:option:`CONFIG_SOC_SERIES_NRF54HX`) to mitigate a negative impact of jitter related to USB polls.
+The negative impact of the jitter is more visible for USB High-Speed.
+
 .. _nrf_desktop_usb_state_hid_class_instance:
 
 USB HID class instance configuration

applications/nrf_desktop/src/modules/Kconfig.usb_state

@@ -59,6 +59,7 @@ config DESKTOP_USB_PM_REQ_NO_PM_LATENCY
 
 config DESKTOP_USB_HID_REPORT_SENT_ON_SOF
 	bool "Submit HID report sent event on USB Start of Frame (SOF) [EXPERIMENTAL]"
+	default y if SOC_SERIES_NRF54HX
 	select EXPERIMENTAL
 	help
 	  Delay submitting hid_report_sent_event until subsequent USB Start of
@@ -67,6 +68,10 @@ config DESKTOP_USB_HID_REPORT_SENT_ON_SOF
 	  report pipeline with two sequential reports is required to ensure that
 	  the USB peripheral can provide a HID report on every USB poll.
 
+	  The feature is enabled by default for nRF54H Series SoC, because the
+	  negative impact of USB polling jitter is more visible in case of USB
+	  High-Speed.
+
 choice DESKTOP_USB_STACK
 	prompt "USB stack"
 	default DESKTOP_USB_STACK_LEGACY

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -278,6 +278,8 @@ nRF Desktop
     Picolibc is used by default in Zephyr.
   * The nRF Desktop application image configurations to use Picolibc (:kconfig:option:`CONFIG_PICOLIBC`) by default.
     Using the minimal libc implementation (:kconfig:option:`CONFIG_MINIMAL_LIBC`) no longer decreases the memory footprint of the application image for most of the configurations.
+  * Enabled :ref:`nrf_desktop_usb_state_sof_synchronization` (:ref:`CONFIG_DESKTOP_USB_HID_REPORT_SENT_ON_SOF <config_desktop_app_options>` Kconfig option) by default on the nRF54H Series SoC (:kconfig:option:`CONFIG_SOC_SERIES_NRF54HX`).
+    The negative impact of USB polling jitter is more visible in case of USB High-Speed.
 
 * Added: