Re: [PATCH] HID: intel-ish-hid: use async resume function

[srinivas pandruvada]

On Sun, 2021-06-13 at 11:25 +0800, Ye Xiang wrote:
> ISH IPC driver uses asynchronous workqueue to do resume now, but there
> is
> a potential timing issue: when child devices resume before bus driver,
> it
> will cause child devices resume failed and cannot be recovered until
> reboot. The current implementation in this case do wait for IPC to
> resume
> but fail to accommodate for a case when there is no ISH reboot and soft
> resume is taking time. This issue is apparent on Tiger Lake platform
> with
> 5.11.13 kernel when doing suspend to idle then resume(s0ix) test. To
> resolve this issue, we change ISHTP HID client to use asynchronous
> resume
> callback too. In the asynchronous resume callback, it waits for the
> ISHTP
> resume done event, and then notify ISHTP HID client link ready.
> 
> Signed-off-by: Ye Xiang <xiang.ye@xxxxxxxxx>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>

> ---
>  drivers/hid/intel-ish-hid/ishtp-hid-client.c | 15 +++++++++-
>  drivers/hid/intel-ish-hid/ishtp-hid.h        |  1 +
>  drivers/hid/intel-ish-hid/ishtp/bus.c        | 29 +++++++++++++++-----
>  include/linux/intel-ish-client-if.h          |  2 ++
>  4 files changed, 39 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hid/intel-ish-hid/ishtp-hid-client.c
> b/drivers/hid/intel-ish-hid/ishtp-hid-client.c
> index 7167412d89d9..9d53e85fdef3 100644
> --- a/drivers/hid/intel-ish-hid/ishtp-hid-client.c
> +++ b/drivers/hid/intel-ish-hid/ishtp-hid-client.c
> @@ -779,6 +779,17 @@ static void hid_ishtp_cl_reset_handler(struct
> work_struct *work)
>         }
>  }
>  
> +static void hid_ishtp_cl_resume_handler(struct work_struct *work)
> +{
> +       struct ishtp_cl_data *client_data = container_of(work, struct
> ishtp_cl_data, resume_work);
> +       struct ishtp_cl *hid_ishtp_cl = client_data->hid_ishtp_cl;
> +
> +       if (ishtp_wait_resume(ishtp_get_ishtp_device(hid_ishtp_cl))) {
> +               client_data->suspended = false;
> +               wake_up_interruptible(&client_data->ishtp_resume_wait);
> +       }
> +}
> +
>  void (*hid_print_trace)(void *unused, const char *format, ...);
>  
>  /**
> @@ -817,6 +828,8 @@ static int hid_ishtp_cl_probe(struct
> ishtp_cl_device *cl_device)
>         init_waitqueue_head(&client_data->ishtp_resume_wait);
>  
>         INIT_WORK(&client_data->work, hid_ishtp_cl_reset_handler);
> +       INIT_WORK(&client_data->resume_work,
> hid_ishtp_cl_resume_handler);
> +
>  
>         hid_print_trace = ishtp_trace_callback(cl_device);
>  
> @@ -918,7 +931,7 @@ static int hid_ishtp_cl_resume(struct device
> *device)
>  
>         hid_ishtp_trace(client_data, "%s hid_ishtp_cl %p\n", __func__,
>                         hid_ishtp_cl);
> -       client_data->suspended = false;
> +       schedule_work(&client_data->resume_work);
>         return 0;
>  }
>  
> diff --git a/drivers/hid/intel-ish-hid/ishtp-hid.h b/drivers/hid/intel-
> ish-hid/ishtp-hid.h
> index 5ffd0da3cf1f..e5fa753fe92f 100644
> --- a/drivers/hid/intel-ish-hid/ishtp-hid.h
> +++ b/drivers/hid/intel-ish-hid/ishtp-hid.h
> @@ -140,6 +140,7 @@ struct ishtp_cl_data {
>         int multi_packet_cnt;
>  
>         struct work_struct work;
> +       struct work_struct resume_work;
>         struct ishtp_cl_device *cl_device;
>  };
>  
> diff --git a/drivers/hid/intel-ish-hid/ishtp/bus.c b/drivers/hid/intel-
> ish-hid/ishtp/bus.c
> index 0d6465f0eaa8..ead6c8f32759 100644
> --- a/drivers/hid/intel-ish-hid/ishtp/bus.c
> +++ b/drivers/hid/intel-ish-hid/ishtp/bus.c
> @@ -329,13 +329,6 @@ static int ishtp_cl_device_resume(struct device
> *dev)
>         if (!device)
>                 return 0;
>  
> -       /*
> -        * When ISH needs hard reset, it is done asynchrnously, hence
> bus
> -        * resume will  be called before full ISH resume
> -        */
> -       if (device->ishtp_dev->resume_flag)
> -               return 0;
> -
>         driver = to_ishtp_cl_driver(dev->driver);
>         if (driver && driver->driver.pm) {
>                 if (driver->driver.pm->resume)
> @@ -863,6 +856,28 @@ struct device *ishtp_device(struct ishtp_cl_device
> *device)
>  }
>  EXPORT_SYMBOL(ishtp_device);
>  
> +/**
> + * ishtp_wait_resume() - Wait for IPC resume
> + *
> + * Wait for IPC resume
> + *
> + * Return: resume complete or not
> + */
> +bool ishtp_wait_resume(struct ishtp_device *dev)
> +{
> +       /* 50ms to get resume response */
> +       #define WAIT_FOR_RESUME_ACK_MS          50
> +
> +       /* Waiting to get resume response */
> +       if (dev->resume_flag)
> +               wait_event_interruptible_timeout(dev->resume_wait,
> +                                                !dev->resume_flag,
> +                                               
> msecs_to_jiffies(WAIT_FOR_RESUME_ACK_MS));
> +
> +       return (!dev->resume_flag);
> +}
> +EXPORT_SYMBOL_GPL(ishtp_wait_resume);
> +
>  /**
>   * ishtp_get_pci_device() - Return PCI device dev pointer
>   * This interface is used to return PCI device pointer
> diff --git a/include/linux/intel-ish-client-if.h b/include/linux/intel-
> ish-client-if.h
> index 1153e0030133..ec3a6ccbece4 100644
> --- a/include/linux/intel-ish-client-if.h
> +++ b/include/linux/intel-ish-client-if.h
> @@ -76,6 +76,8 @@ int ishtp_register_event_cb(struct ishtp_cl_device
> *device,
>  
>  /* Get the device * from ishtp device instance */
>  struct device *ishtp_device(struct ishtp_cl_device *cl_device);
> +/* wait for IPC resume */
> +bool ishtp_wait_resume(struct ishtp_device *dev);
>  /* Trace interface for clients */
>  void *ishtp_trace_callback(struct ishtp_cl_device *cl_device);
>  /* Get device pointer of PCI device for DMA acces */
> 
> base-commit: f5711311bfa1abcc64c6dd1e912666a8c0b29a1a