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

[Greg KH]

On Mon, Dec 16, 2019 at 02:15:12PM +0100, OndÅej Jirman wrote:
> 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.

Is it being fixed in Linus's tree?

thanks,

greg k-h