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SubjectRe: [PATCH AUTOSEL 5.4 133/350] Bluetooth: hci_bcm: Fix RTS handling during startup
Hi,

On Tue, Dec 10, 2019 at 04:03:58PM -0500, Sasha Levin wrote:
> From: Stefan Wahren <wahrenst@gmx.net>
>
> [ Upstream commit 3347a80965b38f096b1d6f995c00c9c9e53d4b8b ]
>
> The RPi 4 uses the hardware handshake lines for CYW43455, but the chip
> doesn't react to HCI requests during DT probe. The reason is the inproper
> handling of the RTS line during startup. According to the startup
> signaling sequence in the CYW43455 datasheet, the hosts RTS line must
> be driven after BT_REG_ON and BT_HOST_WAKE.
>
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> drivers/bluetooth/hci_bcm.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
> index 7646636f2d183..0f73f6a686cb7 100644
> --- a/drivers/bluetooth/hci_bcm.c
> +++ b/drivers/bluetooth/hci_bcm.c
> @@ -445,9 +445,11 @@ static int bcm_open(struct hci_uart *hu)
>
> out:
> if (bcm->dev) {
> + hci_uart_set_flow_control(hu, true);
> hu->init_speed = bcm->dev->init_speed;
> hu->oper_speed = bcm->dev->oper_speed;
> err = bcm_gpio_set_power(bcm->dev, true);
> + hci_uart_set_flow_control(hu, false);
> if (err)
> goto err_unset_hu;
> }

This causes bluetooth breakage (degraded bluetooth performance, due to failure to
switch to higher baudrate) for Orange Pi 3 board:

[ 3.839134] Bluetooth: hci0: command 0xfc18 tx timeout
[ 11.999136] Bluetooth: hci0: BCM: failed to write update baudrate (-110)
[ 12.004613] Bluetooth: hci0: Failed to set baudrate
[ 12.123187] Bluetooth: hci0: BCM: chip id 130
[ 12.128398] Bluetooth: hci0: BCM: features 0x0f
[ 12.154686] Bluetooth: hci0: BCM4345C5
[ 12.157165] Bluetooth: hci0: BCM4345C5 (003.006.006) build 0000
[ 15.343684] Bluetooth: hci0: BCM4345C5 (003.006.006) build 0038

I suggest not pushing this to stable.

regards,
Ondrej

> 2.20.1
>

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