Re: [PATCH 2/2] Bluetooth: btintel_pcie: fix PM flow for S0ix, S3 and S4

[Luiz Augusto von Dentz]

Hi Sergey,

On Wed, Sep 9, 2026 at 8:34 AM Sergey Lebedev <lsa.uz@xxxxx> wrote:
>
> From: Ravindra <ravindra@xxxxxxxxx>
>
> Use pm_suspend_target_state to differentiate S0ix from S3/S4. Set the
> controller to D3_HOT for S0ix (PM_SUSPEND_TO_IDLE) and D3_COLD for
> S3/S4, freeze and hibernate to prevent post-resume instability.
>
> Register .freeze, .thaw, .poweroff and .restore callbacks for proper
> hibernation support. The freeze and poweroff (hibernate) paths set
> D3_COLD via btintel_pcie_suspend_late. The thaw path resumes with a
> normal D0 transition, while .restore forces FLR-based firmware recovery
> after S4 since power is lost. S3 (PM_SUSPEND_MEM) resume also triggers
> FLR. S0ix resumes via a normal D0 transition.
>
> Fixes: e57362f4911b ("Bluetooth: btintel_pcie: Add support for _suspend() / _resume()")
> Assisted-by: GitHub-Copilot:GPT5
> Signed-off-by: Ravindra <ravindra@xxxxxxxxx>
> Assisted-by: Claude:claude-opus-5
> Tested-by: Ferenc Lengyel <dev@xxxxxxxxxxx>
> Signed-off-by: Sergey Lebedev <lsa.uz@xxxxx>
> ---
>  drivers/bluetooth/btintel_pcie.c | 64 ++++++++++++++++++++++----------
>  drivers/bluetooth/btintel_pcie.h |  2 -
>  2 files changed, 44 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
> index 361c550b5..e37e710b9 100644
> --- a/drivers/bluetooth/btintel_pcie.c
> +++ b/drivers/bluetooth/btintel_pcie.c
> @@ -16,6 +16,7 @@
>  #include <linux/delay.h>
>  #include <linux/interrupt.h>
>  #include <linux/acpi.h>
> +#include <linux/suspend.h>
>
>  #include <linux/unaligned.h>
>  #include <linux/devcoredump.h>
> @@ -4168,11 +4169,16 @@ static void btintel_pcie_coredump(struct device *dev)
>
>  static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
>  {
> -       int retry = 0, status;
> +       int retry = 0;
> +       long status;
>         u32 dx_intr_timeout_ms = 200;
>
> +       /* Not reset per retry: dxstate is unchanged, so a late interrupt from
> +        * an earlier attempt still confirms the target state.
> +        */
> +       data->gp0_received = false;
> +
>         do {
> -               data->gp0_received = false;
>
>                 btintel_pcie_wr_sleep_cntrl(data, dxstate);
>
> @@ -4220,18 +4226,23 @@ static int btintel_pcie_suspend_late(struct device *dev, pm_message_t mesg)
>
>         data = pci_get_drvdata(pdev);
>
> -       dxstate = (mesg.event == PM_EVENT_SUSPEND ?
> -                  BTINTEL_PCIE_STATE_D3_HOT : BTINTEL_PCIE_STATE_D3_COLD);
> -
> -       data->pm_sx_event = mesg.event;
> +       /* S0ix (s2idle) uses D3_HOT; S3, freeze and hibernate use D3_COLD. */
> +       if (mesg.event == PM_EVENT_SUSPEND &&
> +           pm_suspend_target_state == PM_SUSPEND_TO_IDLE)
> +               dxstate = BTINTEL_PCIE_STATE_D3_HOT;
> +       else
> +               dxstate = BTINTEL_PCIE_STATE_D3_COLD;
>
>         start = ktime_get();
>
>         /* Refer: 6.4.11.7 -> Platform power management */
>         err = btintel_pcie_set_dxstate(data, dxstate);
>
> -       if (err)
> +       if (err) {
> +               bt_dev_err(data->hdev, "Failed to set dxstate:%u (%d)",
> +                          dxstate, err);
>                 return err;
> +       }
>
>         bt_dev_dbg(data->hdev,
>                    "device entered into d3 state from d0 in %lld us",
> @@ -4254,7 +4265,7 @@ static int btintel_pcie_freeze(struct device *dev)
>         return btintel_pcie_suspend_late(dev, PMSG_FREEZE);
>  }
>
> -static int btintel_pcie_resume(struct device *dev)
> +static int btintel_pcie_resume_event(struct device *dev, pm_message_t mesg)
>  {
>         struct pci_dev *pdev = to_pci_dev(dev);
>         struct btintel_pcie_data *data;
> @@ -4262,19 +4273,15 @@ static int btintel_pcie_resume(struct device *dev)
>         int err;
>
>         data = pci_get_drvdata(pdev);
> -       data->gp0_received = false;
>
>         start = ktime_get();
>
> -       /* When the system enters S4 (hibernate) mode, bluetooth device loses
> -        * power, which results in the erasure of its loaded firmware.
> -        * Consequently, function level reset (flr) is required on system
> -        * resume to bring the controller back into an operational state by
> -        * initiating a new firmware download.
> +       /* S3 and S4 may cut power, erasing the firmware. Force FLR to recover
> +        * instead of a normal D0 transition.
>          */
> -
> -       if (data->pm_sx_event == PM_EVENT_FREEZE ||
> -           data->pm_sx_event == PM_EVENT_HIBERNATE) {
> +       if (mesg.event == PM_EVENT_RESTORE ||
> +           (mesg.event == PM_EVENT_RESUME &&
> +            pm_suspend_target_state == PM_SUSPEND_MEM)) {
>                 set_bit(BTINTEL_PCIE_CORE_HALTED, &data->flags);
>                 btintel_pcie_request_reset(data, BTINTEL_PCIE_IOSF_PRR_FLR);
>                 return 0;
> @@ -4283,7 +4290,9 @@ static int btintel_pcie_resume(struct device *dev)
>         /* Refer: 6.4.11.7 -> Platform power management */
>         err = btintel_pcie_set_dxstate(data, BTINTEL_PCIE_STATE_D0);
>
> -       if (err == 0) {
> +       if (err) {
> +               bt_dev_err(data->hdev, "Failed to set D0 state (%d)", err);
> +       } else {
>                 bt_dev_dbg(data->hdev,
>                            "device entered into d0 state from d3 in %lld us",
>                            ktime_to_us(ktime_get() - start));
> @@ -4308,13 +4317,28 @@ static int btintel_pcie_resume(struct device *dev)
>         return err;
>  }
>
> +static int btintel_pcie_resume(struct device *dev)
> +{
> +       return btintel_pcie_resume_event(dev, PMSG_RESUME);
> +}
> +
> +static int btintel_pcie_restore(struct device *dev)
> +{
> +       return btintel_pcie_resume_event(dev, PMSG_RESTORE);
> +}
> +
> +static int btintel_pcie_thaw(struct device *dev)
> +{
> +       return btintel_pcie_resume_event(dev, PMSG_THAW);
> +}
> +
>  static const struct dev_pm_ops btintel_pcie_pm_ops = {
>         .suspend = btintel_pcie_suspend,
>         .resume = btintel_pcie_resume,
>         .freeze = btintel_pcie_freeze,
> -       .thaw = btintel_pcie_resume,
> +       .thaw = btintel_pcie_thaw,
>         .poweroff = btintel_pcie_hibernate,
> -       .restore = btintel_pcie_resume,
> +       .restore = btintel_pcie_restore,
>  };
>
>  static struct pci_driver btintel_pcie_driver = {
> diff --git a/drivers/bluetooth/btintel_pcie.h b/drivers/bluetooth/btintel_pcie.h
> index 016795fcb..3030b4e8b 100644
> --- a/drivers/bluetooth/btintel_pcie.h
> +++ b/drivers/bluetooth/btintel_pcie.h
> @@ -713,7 +713,6 @@ struct btintel_pcie_ini_dump_info {
>   * @txq: TX Queue struct
>   * @rxq: RX Queue struct
>   * @alive_intr_ctxt: Alive interrupt context
> - * @pm_sx_event: PM event on which system got suspended
>   */
>  struct btintel_pcie_data {
>         struct pci_dev  *pdev;
> @@ -773,7 +772,6 @@ struct btintel_pcie_data {
>         struct btintel_pcie_dbgc        dbgc;
>         struct btintel_pcie_mdbgc       mdbgc;
>         struct btintel_pcie_dump_header dmp_hdr;
> -       u8      pm_sx_event;
>         u32     debug_evt_addr;
>         u32     debug_evt_size;
>         dma_addr_t      debug_table_addr;
> --
> 2.50.1 (Apple Git-155)

Sashiko flagged a few things:

https://sashiko.dev/#/patchset/20260909123416.71919-1-lsa.uz%40pm.me

-- 
Luiz Augusto von Dentz