Merge pull request #3633 from hathach/fix/nrf5x-hfclk-wait-post-sd

nrf5x: request HFCLK in USB_EVT_READY to fix post-SoftDevice deadlock

1 files changed, 6 insertions, 0 deletions

diff --git a/src/portable/nordic/nrf5x/dcd_nrf5x.c b/src/portable/nordic/nrf5x/dcd_nrf5x.c
index 6ed5fde8e..befbaa338 100644
--- a/src/portable/nordic/nrf5x/dcd_nrf5x.c
+++ b/src/portable/nordic/nrf5x/dcd_nrf5x.c
@@ -1049,6 +1049,12 @@ void tusb_hal_nrf_power_event(uint32_t event) {
         NVIC_EnableIRQ(USBD_IRQn);
       }
 
+      // Ensure HFCLK is requested in the current context. The hfclk_enable() in
+      // USB_EVT_DETECTED may have been pre-SoftDevice. After Softdevice is
+      // enabled, HFXO is physically off again. So any caller that fires
+      // USB_EVT_READY post-SD would hang here.
+      hfclk_enable();
+
       // Wait for HFCLK
       while (!hfclk_running()) {}