applications: nrf_desktop: Use high Global Domain frequency on nRF54H20

In nRF Desktop application, the DVFS module running on the application
core selects clock control and enables automatic low GD frequency
request. Update IPC radio configuration to ensure high GD frequency,
which is required to ensure stability of the Bluetooth stack with
SoftDevice Link Layer.

Jira: NCSDK-31824

Signed-off-by: Marek Pieta <[email protected]>
Signed-off-by: Piotr Pryga <[email protected]>
Signed-off-by: Pekka Niskanen <[email protected]>

Author: MarekPieta

applications/nrf_desktop/configuration/nrf54h20dk_nrf54h20_cpurad/images/ipc_radio/prj.conf

@@ -44,6 +44,9 @@ CONFIG_SPEED_OPTIMIZATIONS=y
 CONFIG_LTO=y
 CONFIG_ISR_TABLES_LOCAL_DECLARATION=y
 
+# Bluetooth stack with SoftDevice Link Layer requires high frequency in Global Domain (GD) to make L2 cache and MRAM run fast to avoid code execution delays.
+CONFIG_CLOCK_CONTROL_NRF2_GLOBAL_HSFLL_REQ_LOW_FREQ=n
+
 ################################################################################
 # Debug logs
 

applications/nrf_desktop/configuration/nrf54h20dk_nrf54h20_cpurad/images/ipc_radio/prj_release.conf

@@ -41,6 +41,9 @@ CONFIG_SPEED_OPTIMIZATIONS=y
 CONFIG_LTO=y
 CONFIG_ISR_TABLES_LOCAL_DECLARATION=y
 
+# Bluetooth stack with SoftDevice Link Layer requires high frequency in Global Domain (GD) to make L2 cache and MRAM run fast to avoid code execution delays.
+CONFIG_CLOCK_CONTROL_NRF2_GLOBAL_HSFLL_REQ_LOW_FREQ=n
+
 ################################################################################
 # Disable unused features
 

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

@@ -246,6 +246,12 @@ nRF Desktop
     * Disabled Bluetooth long workqueue (:kconfig:option:`CONFIG_BT_LONG_WQ`).
     * Limited the number of key slots in the PSA Crypto core to 10 (:kconfig:option:`CONFIG_MBEDTLS_PSA_KEY_SLOT_COUNT`).
 
+  * Disabled the :kconfig:option:`CONFIG_CLOCK_CONTROL_NRF2_GLOBAL_HSFLL_REQ_LOW_FREQ` Kconfig option in the IPC radio image configuration for the nRF54H20 SoC.
+    This is done to ensure that the radio core requests high Global Domain (GD) frequency.
+    The option was enabled by default, because the clock control is enabled by the Multiprotocol Service Layer (MPSL).
+    Bluetooth stack with the SoftDevice Link Layer requires high frequency in GD to make the L2 cache and MRAM run fast to avoid code execution delays.
+    The :ref:`nrf_desktop_dvfs` running on the application core selects the clock control and enables an automatic low GD frequency request (:kconfig:option:`CONFIG_CLOCK_CONTROL_NRF2_GLOBAL_HSFLL_REQ_LOW_FREQ`), so the application core would not request high frequency in the GD.
+
 * Added:
 
   * System Power Management for the :ref:`zephyr:nrf54h20dk_nrf54h20` board target on the application and radio cores.