applications: nrf_desktop: Imply CONFIG_BT_CONN_TX_NOTIFY_WQ

Change conditionally implies CONFIG_BT_CONN_TX_NOTIFY_WQ to work around
the MPSL flash synchronization timeout known issue.

Jira: NCSDK-29354

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

Author: MarekPieta

applications/nrf_desktop/Kconfig.ble

@@ -15,13 +15,18 @@ config DESKTOP_BT
 	select BT_SETTINGS
 	select BT_SIGNING
 	select BT_SMP
+	imply BT_CONN_TX_NOTIFY_WQ if SOC_FLASH_NRF_RADIO_SYNC_MPSL
 	help
 	  Enable support for Bluetooth connectivity in the nRF Desktop
 	  application. Specific Bluetooth configurations and application
 	  modules are selected according to the HID device role. Apart from
 	  that, the defaults of Bluetooth-related Kconfigs are aligned with
 	  the nRF Desktop use case.
 
+	  nRF Desktop conditionally implies using a separate workqueue for
+	  connection TX notify processing. This is done to work around the MPSL
+	  flash synchronization timeout known issue (NCSDK-29354).
+
 if DESKTOP_BT
 
 config DESKTOP_BT_PERIPHERAL

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

@@ -328,6 +328,9 @@ nRF Desktop
   * The USB next stack (:ref:`CONFIG_DESKTOP_USB_STACK_NEXT <config_desktop_app_options>`) implies partial erase feature of the nRF SoC flash driver (:kconfig:option:`CONFIG_SOC_FLASH_NRF_PARTIAL_ERASE`).
     This is done to improve stability of the USB next stack.
     The partial erase feature works around device errors that might be reported by Windows USB host in Device Manager if USB cable is connected while erasing secondary image slot in the background.
+  * Bluetooth connectivity support (:ref:`CONFIG_DESKTOP_BT <config_desktop_app_options>`) implies using a separate workqueue for connection TX notify processing (:kconfig:option:`CONFIG_BT_CONN_TX_NOTIFY_WQ`) if MPSL is used for synchronization between the flash memory driver and radio (:kconfig:option:`CONFIG_SOC_FLASH_NRF_RADIO_SYNC_MPSL`).
+    This is done to work around the timeout in MPSL flash synchronization (``NCSDK-29354`` known issue).
+    See :ref:`known_issues` for details.
 
 * Updated: