Increase BLE background scan window for faster re-connection

The scan window is increased from 11.25ms to 30ms.
The scan duty cycle is still very low at 2.34% while user experience
is greatly improved.
bug 16521059

Change-Id: Ice37c54fdc7d852fd19709112075e7492b6a1480

parent 961137a0

system/stack/include/btm_ble_api.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -135,7 +135,7 @@ typedef UINT8 tBTM_BLE_SFP;
		#define BTM_BLE_SCAN_SLOW_INT_1 2048 /* 1.28 s = 2048 0.625 /
		#endif
		#ifndef BTM_BLE_SCAN_SLOW_WIN_1
		#define BTM_BLE_SCAN_SLOW_WIN_1 18 /* 11.25 ms = 18 0.625 /
		#define BTM_BLE_SCAN_SLOW_WIN_1 48 /* 30 ms = 48 0.625 /
		#endif

		/* default scan paramter used in reduced power cycle (background scanning) */