@@ -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)
On most devices using the btqcomsmd driver (e.g. the DragonBoard 410c and other devices based on the Qualcomm MSM8916/MSM8909/... SoCs) the Bluetooth firmware seems to become unresponsive for a while after setting the BD address. On recent kernel versions (at least 5.17+) 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. Older kernel versions are likely also affected, although perhaps with slightly different errors or less probability. Side effects can easily hide the issue in most cases, e.g. unrelated incoming interrupts that cause the necessary delay. Fixes: 1511cc750c3d ("Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver") Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com> --- 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). Changes in v2: - Clarify commit message: Add affected devices and kernel versions v1: https://lore.kernel.org/linux-bluetooth/20220613110745.3778356-1-stephan.gerhold@kernkonzept.com/ --- drivers/bluetooth/btqcomsmd.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)