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

[Praveen Talari <praveen.talari@oss.qualcomm.com>]

Hi

On 1/7/2026 12:52 PM, Dmitry Baryshkov wrote:
> On Wed, 7 Jan 2026 at 09:06, Praveen Talari
> <praveen.talari@oss.qualcomm.com> 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@oss.qualcomm.com> 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?

During the runtime resume of devices, GPIOs are configured to QUP mode. 
However, when registering the wakeup IRQ using 
dev_pm_set_dedicated_wake_irq(), these GPIOs are reset back to FUNC 
mode, which impacts the RX GPIO and leads to Bluetooth failures

Thanks,
Praveen
> 
>>
>> 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@oss.qualcomm.com>
>>>> Closes:
>>>> https://lore.kernel.org/all/20251110101043.2108414-4-praveen.talari@oss.qualcomm.com/
>>>> Fixes: 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial driver")
>>>> Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
>>>> ---
>>>>    drivers/tty/serial/qcom_geni_serial.c | 12 ++++++------
>>>>    1 file changed, 6 insertions(+), 6 deletions(-)
>>>>
>>>
>>> Tested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
>>>
>>>
>>
> 
>