On Fri, Jan 18, 2019 at 10:44:16AM +0100, Johan Hovold wrote: > On Thu, Jan 17, 2019 at 09:21:09AM -0800, Matthias Kaehlcke wrote: > > > I observed that the qcom_geni_serial driver doesn't raise RTS with > > flow control disabled. It seems we have to investigate why that's the > > case. I agree that the driver should be platform agnostic. > > Sounds like a driver bug, unless the hardware is just "odd". The > driver implementation of this looks very non-standard judging from a > quick peek. > > In fact, qcom_geni_serial_get_mctrl() is currently a no-op if hardware > flow control is not enabled: > > if (uart_console(uport) || !uart_cts_enabled(uport)) > return; > > Perhaps dropping the !uart_cts_enabled() test is sufficient. Thanks for taking a look Johan, that was indeed the problem (also in set_mctrl()). I posted a fix: https://lore.kernel.org/patchwork/patch/1033611/ Balakrishna, the following (applied on top of your patch) works for me with the UART patch above: diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c index 9d5e41f159c78f..60bfdf01f72841 100644 --- a/drivers/bluetooth/hci_qca.c +++ b/drivers/bluetooth/hci_qca.c @@ -1080,7 +1080,7 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type) { unsigned int speed, qca_baudrate; struct qca_serdev *qcadev; - int ret; + int ret = 0; if (speed_type == QCA_INIT_SPEED) { speed = qca_get_speed(hu, QCA_INIT_SPEED); @@ -1097,22 +1097,27 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type) * the old speed. */ qcadev = serdev_device_get_drvdata(hu->serdev); - if (qcadev->btsoc_type == QCA_WCN3990) + if (qcadev->btsoc_type == QCA_WCN3990) { + hci_uart_set_flow_control(hu, true); serdev_device_set_rts(hu->serdev, false); + } qca_baudrate = qca_get_baudrate_value(speed); bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed); ret = qca_set_baudrate(hu->hdev, qca_baudrate); if (ret) - return ret; + goto out; host_set_baudrate(hu, speed); - if (qcadev->btsoc_type == QCA_WCN3990) +out: + if (qcadev->btsoc_type == QCA_WCN3990) { + hci_uart_set_flow_control(hu, false); serdev_device_set_rts(hu->serdev, true); + } } - return 0; + return ret; } static int qca_wcn3990_init(struct hci_uart *hu)
