Hi Luiz,
It looks like this patch will get archived again in patchwork end of
this week. Is there anything I can change to make it acceptable?
This is a fairly important fix to have Bluetooth working on these
devices, since it fails to initialize most of the times without it.
Thanks!
Stephan
On Tue, Oct 18, 2022 at 10:54:31AM +0200, Stephan Gerhold wrote:
> 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@xxxxxxxxxxxxxxx>
> ---
> (Unmodified resend of the v2 I sent back in June, it seems to have
> disappeared from patchwork)
>
> 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
> ---
> 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
>
