From: Stephan Gerhold stephan.gerhold@kernkonzept.com
[ Upstream commit 5d44ab9e204200a78ad55cdf185aa2bb109b5950 ]
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 Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 874172aa8e417..a698b1f6394b2 100644 --- a/drivers/bluetooth/btqcomsmd.c +++ b/drivers/bluetooth/btqcomsmd.c @@ -146,6 +146,21 @@ 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; @@ -195,7 +210,7 @@ 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)