Bluetooth: Add quirk to disable extended scanning

Broadcom 4377 controllers found in Apple x86 Macs with the T2 chip
claim to support extended scanning when querying supported states,

< HCI Command: LE Read Supported St.. (0x08|0x001c) plen 0  #27 [hci0] 2.971839
> HCI Event: Command Complete (0x0e) plen 12                #28 [hci0] 2.972730
      LE Read Supported States (0x08|0x001c) ncmd 1
        Status: Success (0x00)
        States: 0x000003ffffffffff
[...]
          LE Set Extended Scan Parameters (Octet 37 - Bit 5)
          LE Set Extended Scan Enable (Octet 37 - Bit 6)
[...]

, but then fail to actually implement the extended scanning:

< HCI Command: LE Set Extended Sca.. (0x08|0x0041) plen 8  #105 [hci0] 5.460776
        Own address type: Random (0x01)
        Filter policy: Accept all advertisement (0x00)
        PHYs: 0x01
        Entry 0: LE 1M
          Type: Active (0x01)
          Interval: 11.250 msec (0x0012)
          Window: 11.250 msec (0x0012)
> HCI Event: Command Complete (0x0e) plen 4                #106 [hci0] 5.461777
      LE Set Extended Scan Parameters (0x08|0x0041) ncmd 1
        Status: Unknown HCI Command (0x01)

Signed-off-by: Sven Peter <sven@svenpeter.dev>

Author: svenpeter42

include/net/bluetooth/hci.h

@@ -274,6 +274,16 @@ enum {
 	 * during the hdev->setup vendor callback.
 	 */
 	HCI_QUIRK_FIXUP_LE_EXT_ADV_REPORT_EVT_TYPE,
+
+	/*
+	 * When this quirk is set, the HCI_OP_LE_SET_EXT_SCAN_ENABLE command is
+	 * disabled. This is required for some Broadcom controllers which
+	 * erroneously claim to support extended scanning.
+	 *
+	 * This quirk can be set before hci_register_dev is called or
+	 * during the hdev->setup vendor callback.
+	 */
+	HCI_QUIRK_BROKEN_EXT_SCAN,
 };
 
 /* HCI device flags */

include/net/bluetooth/hci_core.h

@@ -1681,7 +1681,9 @@ void hci_conn_del_sysfs(struct hci_conn *conn);
 
 /* Use ext scanning if set ext scan param and ext scan enable is supported */
 #define use_ext_scan(dev) (((dev)->commands[37] & 0x20) && \
-			   ((dev)->commands[37] & 0x40))
+			   ((dev)->commands[37] & 0x40) && \
+			   !test_bit(HCI_QUIRK_BROKEN_EXT_SCAN, &(dev)->quirks))
+
 /* Use ext create connection if command is supported */
 #define use_ext_conn(dev) ((dev)->commands[37] & 0x80)