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

[OndÅej Jirman]

Hi,

On Tue, Dec 10, 2019 at 04:03:58PM -0500, Sasha Levin wrote:
> From: Stefan Wahren <wahrenst@xxxxxxx>
> 
> [ 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@xxxxxxx>
> Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
>  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
>