Hello, On Sun, Oct 20, 2019 at 11:17:28PM +0200, Stefan Wahren wrote: > Hi Marcel, > hi Johan, > > Am 06.10.19 um 17:28 schrieb Stefan Wahren: > > 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> > > --- > > 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 7646636..0f73f6a 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; > > } > > -- > > 2.7.4 > > would be nice to get some feedback about this. I started seeing failures on Orange Pi 3 in 5.5-rc: [ 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 Switch to higher baudrate works again after reverting this patch. That board also uses RTS/CTS signalling. I guess the patch needs re-thinking/maybe other chips may not need this? I don't have access to datasheets. regards, o. > Regards > Stefan > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel