Re: [PATCH v2] serial: qcom_geni: Fix BT failure regression on RB2 platform

[Praveen Talari]

Hi Mayank,

Thank you for the review.

On 1/8/2026 3:09 AM, Mayank Rana wrote:
> On 1/7/2026 8:26 AM, Praveen Talari wrote:
> > Commit 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial
> > driver") caused BT init to fail during bootup on the RB2 platform,
> > preventing proper BT initialization. However, BT works correctly after
> > bootup completes.
> >
> > The issue occurs when runtime PM is enabled and uart_add_one_port() is
> > called before wakeup IRQ setup. The uart_add_one_port() call activates
> > the device through runtime PM, which configures GPIOs to the "qup_x"
> > pinmux function during runtime resume. When wakeup IRQ registration
> > happens afterward using dev_pm_set_dedicated_wake_irq(), these GPIOs
> > are reset back to the "gpio" pinmux function, which impacts the RX GPIO
> > and leads to Bluetooth failures.
> >
> > Fix this by ensuring wakeup IRQ setup is completed before calling
> > uart_add_one_port() to prevent the pinmux function conflict.
> >
> > Tested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > Reported-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> > Closes: https://lore.kernel.org/all/20251110101043.2108414-4- 
> > praveen.talari@xxxxxxxxxxxxxxxx/
> > Fixes: 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial 
> > driver")
> > Signed-off-by: Praveen Talari <praveen.talari@xxxxxxxxxxxxxxxx>
> > ---
> > v1 -> v2
> > - Updated commit text.
> > - Added Tested-by in commit text
> > ---
> >   drivers/tty/serial/qcom_geni_serial.c | 12 ++++++------
> >   1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/ 
> > serial/qcom_geni_serial.c
> > index 6ce6528f5c10..46a9c71630d5 100644
> > --- a/drivers/tty/serial/qcom_geni_serial.c
> > +++ b/drivers/tty/serial/qcom_geni_serial.c
> > @@ -1888,12 +1888,6 @@ static int qcom_geni_serial_probe(struct 
> > platform_device *pdev)
> >       if (ret)
> >           goto error;
> > -    devm_pm_runtime_enable(port->se.dev);
> > -
> > -    ret = uart_add_one_port(drv, uport);
> > -    if (ret)
> > -        goto error;
> > -
> >       if (port->wakeup_irq > 0) {
> >           device_init_wakeup(&pdev->dev, true);
> >           ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
>
> do you need to handle error handling part here as calling 
> uart_remove_one_port() shall result into NULL access related crash while 
> accessing port->port_dev as port_dev is not allocated 
> (serial_base_port_add() add is not being called due to moving 
> uart_add_one_port() later)

Yes, you are correct. Will address it in next patch.

Thanks,
Praveen Talari

> --- a/drivers/tty/serial/qcom_geni_serial.c
> +++ b/drivers/tty/serial/qcom_geni_serial.c
> @@ -1901,7 +1901,6 @@ static int qcom_geni_serial_probe(struct 
> platform_device *pdev)
>                  if (ret) {
>                          device_init_wakeup(&pdev->dev, false);
>                          ida_free(&port_ida, uport->line);
> -                       uart_remove_one_port(drv, uport);
>                          goto error;
>                  }
>          }
>
> > @@ -1906,6 +1900,12 @@ static int qcom_geni_serial_probe(struct 
> > platform_device *pdev)
> >           }
> >       }
> > +    devm_pm_runtime_enable(port->se.dev);
> > +
> > +    ret = uart_add_one_port(drv, uport);
> > +    if (ret)
> > +        goto error;
> > +
> >       return 0;
> >   error:
> >
> > base-commit: 6cd6c12031130a349a098dbeb19d8c3070d2dfbe
> Regards,
> Mayank