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 >