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@oss.qualcomm.com>
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>
---
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,
@@ -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
-- 
2.34.1

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@oss.qualcomm.com>
> 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>
> ---
> 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)

--- 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

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@oss.qualcomm.com>
>> 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>
>> ---
>> 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

On Wed, Jan 07, 2026 at 09:56:10PM +0530, 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@oss.qualcomm.com>
> 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")

The order of tags is odd. How can it be tested before being reported?
I'd suggest the following order:
- Fixes
- Reported-by
- Closes
- Tested-by
- Reviewed-by

> Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
> ---
> 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(-)
> 

With the tag order fixed:

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

-- 
With best wishes
Dmitry

Hi Dmistry,

Thank you for your inputs.

On 1/7/2026 11:11 PM, Dmitry Baryshkov wrote:
> On Wed, Jan 07, 2026 at 09:56:10PM +0530, 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@oss.qualcomm.com>
>> 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")
> 
> The order of tags is odd. How can it be tested before being reported?
> I'd suggest the following order:
> - Fixes
> - Reported-by
> - Closes
> - Tested-by
> - Reviewed-by

Thank you for your inputs. Will do it in next patch.

Thanks,
Praveen Talari
> 
>> Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
>> ---
>> 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(-)
>>
> 
> With the tag order fixed:
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
>