The Bluetooth firmware seems to become unresponsive for a while after
setting the BD address. At least on recent kernel versions this often
causes timeouts for subsequent commands, e.g. the HCI reset sent by
the Bluetooth core during initialization:
Bluetooth: hci0: Opcode 0x c03 failed: -110
Unfortunately this behavior does not seem to be documented anywhere.
Experimentation suggests that the minimum necessary delay to avoid
the problem is ~150us. However, to be sure add a sleep for > 1ms
in case it is a bit longer on other firmware versions.
Fixes: 1511cc750c3d ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver")
Signed-off-by: Stephan Gerhold <stephan.gerhold@xxxxxxxxxxxxxxx>
---
I tested this using a script that reboots repeatedly and checks for the
error. With this patch, BT shows up successfully for 100+ consecutive
boots. Without this patch it usually fails after 1-5 boots (or even
always on some boards).
---
drivers/bluetooth/btqcomsmd.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/bluetooth/btqcomsmd.c b/drivers/bluetooth/btqcomsmd.c
index 2acb719e596f..11c7e04bf394 100644
--- a/drivers/bluetooth/btqcomsmd.c
+++ b/drivers/bluetooth/btqcomsmd.c
@@ -122,6 +122,21 @@ static int btqcomsmd_setup(struct hci_dev *hdev)
return 0;
}
+static int btqcomsmd_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
+{
+ int ret;
+
+ ret = qca_set_bdaddr_rome(hdev, bdaddr);
+ if (ret)
+ return ret;
+
+ /* The firmware stops responding for a while after setting the bdaddr,
+ * causing timeouts for subsequent commands. Sleep a bit to avoid this.
+ */
+ usleep_range(1000, 10000);
+ return 0;
+}
+
static int btqcomsmd_probe(struct platform_device *pdev)
{
struct btqcomsmd *btq;
@@ -162,7 +177,7 @@ static int btqcomsmd_probe(struct platform_device *pdev)
hdev->close = btqcomsmd_close;
hdev->send = btqcomsmd_send;
hdev->setup = btqcomsmd_setup;
- hdev->set_bdaddr = qca_set_bdaddr_rome;
+ hdev->set_bdaddr = btqcomsmd_set_bdaddr;
ret = hci_register_dev(hdev);
if (ret < 0)
--
2.30.2
