Re: [PATCH v1] serial: qcom_geni: Fix BT failure regression on RB2 platform

[Dmitry Baryshkov]

On Wed, 7 Jan 2026 at 09:06, Praveen Talari
<praveen.talari@xxxxxxxxxxxxxxxx> wrote:
>
> Hi Dmistry,
>
> On 1/7/2026 12:24 PM, Dmitry Baryshkov wrote:
> > On Wed, 7 Jan 2026 at 08:48, Praveen Talari
> > <praveen.talari@xxxxxxxxxxxxxxxx> wrote:
> >>
> >> A regression in linux-next causes Bluetooth functionality to fail during
> >
> > linux-next is an ephemeral thing. Please reference the exact commit.
> >
> >> 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 their default state.
> >> When wakeup IRQ registration happens afterward, it conflicts with these
> >> GPIO settings, causing state corruption that breaks Bluetooth
> >> functionality.
> >
> > How does it "conflict with GPIO settings", what is "state corruption"?
>
> I mean the issue occurs because the GPIO state is being altered during
> the wakeup source registration process..

Altered how?

>
> Thanks,
> Praveen Talari
> >
> >
> >>
> >> Fix this by moving runtime PM enablement and uart_add_one_port() after
> >> wakeup IRQ registration, ensuring proper initialization order.
> >>
> >> 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>
> >> ---
> >>   drivers/tty/serial/qcom_geni_serial.c | 12 ++++++------
> >>   1 file changed, 6 insertions(+), 6 deletions(-)
> >>
> >
> > Tested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
> >
> >
>


-- 
With best wishes
Dmitry