linux-kernel - Re: [PATCH v1 3/4] serial: qcom-geni: Enable PM runtime for serial driver

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Message-ID: <8c734f2d-59db-4815-bfc6-3823cf3ef37a@oss.qualcomm.com>
Date: Wed, 31 Dec 2025 08:30:01 +0530
From: Praveen Talari <praveen.talari@....qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>, Dmitry Baryshkov <lumag@...nel.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-serial@...r.kernel.org, alexey.klimov@...aro.org,
        krzk@...nel.org, bryan.odonoghue@...aro.org,
        jorge.ramirez@....qualcomm.com,
        Konrad Dybcio <konrad.dybcio@....qualcomm.com>, psodagud@...cinc.com,
        djaggi@...cinc.com, quic_msavaliy@...cinc.com,
        quic_vtanuku@...cinc.com, quic_arandive@...cinc.com,
        quic_shazhuss@...cinc.com, quic_cchiluve@...cinc.com
Subject: Re: [PATCH v1 3/4] serial: qcom-geni: Enable PM runtime for serial
 driver

Hi Dmitry,

On 12/30/2025 11:53 PM, Dmitry Baryshkov wrote:
> On Mon, Nov 10, 2025 at 03:40:42PM +0530, Praveen Talari wrote:
>> The GENI serial driver currently handles power resource management
>> through calls to the statically defined geni_serial_resources_on() and
>> geni_serial_resources_off() functions. This approach reduces modularity
>> and limits support for platforms with diverse power management
>> mechanisms, including resource managed by firmware.
>>
>> Improve modularity and enable better integration with platform-specific
>> power management, introduce support for runtime PM. Use
>> pm_runtime_resume_and_get() and pm_runtime_put_sync() within the
>> qcom_geni_serial_pm() callback to control resource power state
>> transitions based on UART power state changes.
>>
>> Signed-off-by: Praveen Talari <praveen.talari@....qualcomm.com>
>> ---
>>   drivers/tty/serial/qcom_geni_serial.c | 24 ++++++++++++++++++++++--
>>   1 file changed, 22 insertions(+), 2 deletions(-)
>>
> 
> This breaks BT support on the Qualcomm RB2 platform. With this patch
> applied, I'm getting the following:
> 
> root@...m-armv8a:~# dmesg | grep tty\\\|hci0
> [    0.000000] Kernel command line:  ignore_loglevel console=ttyMSM0,115200n8 earlycon root=PARTLABEL=rootfs rootwait systemd.mask=pd-mapper.service --   androidboot.bootdevice=4744000.sdhci androidboot.serialno=2b89b520 androidboot.baseband=apq msm_drm.dsi_display0=qcom,mdss_dsi_ext_bridge_1080p:
> [    4.074354] 4a8c000.serial: ttyHS1 at MMIO 0x4a8c000 (irq = 140, base_baud = 0) is a MSM
> [    4.099410] serial serial0: tty port ttyHS1 registered
> [    4.131200] Bluetooth: hci0: setting up wcn399x
> [    4.149847] 4a90000.serial: ttyMSM0 at MMIO 0x4a90000 (irq = 142, base_baud = 0) is a MSM
> [    4.229099] printk: legacy console [ttyMSM0] enabled
> [    6.499519] Bluetooth: hci0: command 0xfc00 tx timeout
> [    6.514347] Bluetooth: hci0: Reading QCA version information failed (-110)
> [    6.559933] Bluetooth: hci0: Retry BT power ON:0
> [    8.016330] systemd[1]: Created slice Slice /system/getty.
> [    8.066194] systemd[1]: Created slice Slice /system/serial-getty.
> [    8.148389] systemd[1]: Expecting device /dev/ttyMSM0...
> [    8.956804] Bluetooth: hci0: command 0xfc00 tx timeout
> [    8.962447] Bluetooth: hci0: Reading QCA version information failed (-110)
> [    8.976917] Bluetooth: hci0: Retry BT power ON:1
> [   11.296715] Bluetooth: hci0: command 0xfc00 tx timeout
> [   11.302340] Bluetooth: hci0: Reading QCA version information failed (-110)
> [   11.309534] Bluetooth: hci0: Retry BT power ON:2
> [   13.660078] Bluetooth: hci0: command 0xfc00 tx timeout
> [   13.665814] Bluetooth: hci0: Reading QCA version information failed (-110)

Sure, will check and update.

If possible, can you share what is DT filename for RB2.

Earlier I had validated on RB1 and Kodiak.

Thanks,
Praveen

> 
> After reverting the next and this patches, BT is back to normal:
> 
> [    4.067201] 4a8c000.serial: ttyHS1 at MMIO 0x4a8c000 (irq = 140, base_baud = 0) is a MSM
> [    4.082426] serial serial0: tty port ttyHS1 registered
> [    4.106122] 4a90000.serial: ttyMSM0 at MMIO 0x4a90000 (irq = 142, base_baud = 0) is a MSM
> [    4.108647] Bluetooth: hci0: setting up wcn399x
> [    4.125371] printk: legacy console [ttyMSM0] enabled
> [    4.445205] Bluetooth: hci0: QCA Product ID   :0x0000000a
> [    4.450927] Bluetooth: hci0: QCA SOC Version  :0x40020150
> [    4.456470] Bluetooth: hci0: QCA ROM Version  :0x00000201
> [    4.462006] Bluetooth: hci0: QCA Patch Version:0x00000001
> [    4.509408] Bluetooth: hci0: QCA controller version 0x01500201
> [    4.515656] Bluetooth: hci0: QCA Downloading qca/apbtfw11.tlv
> [    5.488739] Bluetooth: hci0: QCA Downloading qca/apnv11.bin
> [    5.671740] Bluetooth: hci0: QCA setup on UART is completed
> [    7.993368] systemd[1]: Created slice Slice /system/getty.
> [    8.045612] systemd[1]: Created slice Slice /system/serial-getty.
> [    8.125418] systemd[1]: Expecting device /dev/ttyMSM0...
> 
>