Re: [PATCH 2/3] HID: logitech-hidpp: Don't restart communication if not necessary

[Bastien Nocera <hadess@hadess.net>]

On Tue, 2022-12-20 at 10:22 +0100, Bastien Nocera wrote:
> Don't stop and restart communication with the device unless we need
> to
> modify the connect flags used because of a device quirk.

FIWW, Andreas Bergmeier told me off-list that this fixed their problem
with the Litra Glow not connecting properly.

Would be great to have reviews on this and my other HID++ patches.

Cheers

> ---
>  drivers/hid/hid-logitech-hidpp.c | 31 +++++++++++++++++++-----------
> -
>  1 file changed, 19 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-
> logitech-hidpp.c
> index 7f9187201913..b4e4a8c79c75 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -4310,6 +4310,7 @@ static int hidpp_probe(struct hid_device *hdev,
> const struct hid_device_id *id)
>         bool connected;
>         unsigned int connect_mask = HID_CONNECT_DEFAULT;
>         struct hidpp_ff_private_data data;
> +       bool will_restart = false;
>  
>         /* report_fixup needs drvdata to be set before we call
> hid_parse */
>         hidpp = devm_kzalloc(&hdev->dev, sizeof(*hidpp), GFP_KERNEL);
> @@ -4360,6 +4361,9 @@ static int hidpp_probe(struct hid_device *hdev,
> const struct hid_device_id *id)
>                         return ret;
>         }
>  
> +       if (hidpp->quirks & HIDPP_QUIRK_DELAYED_INIT)
> +               will_restart = true;
> +
>         INIT_WORK(&hidpp->work, delayed_work_cb);
>         mutex_init(&hidpp->send_mutex);
>         init_waitqueue_head(&hidpp->wait);
> @@ -4374,7 +4378,7 @@ static int hidpp_probe(struct hid_device *hdev,
> const struct hid_device_id *id)
>          * Plain USB connections need to actually call start and open
>          * on the transport driver to allow incoming data.
>          */
> -       ret = hid_hw_start(hdev, 0);
> +       ret = hid_hw_start(hdev, will_restart ? 0 : connect_mask);
>         if (ret) {
>                 hid_err(hdev, "hw start failed\n");
>                 goto hid_hw_start_fail;
> @@ -4411,6 +4415,7 @@ static int hidpp_probe(struct hid_device *hdev,
> const struct hid_device_id *id)
>                         hidpp->wireless_feature_index = 0;
>                 else if (ret)
>                         goto hid_hw_init_fail;
> +               ret = 0;
>         }
>  
>         if (connected && (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)) {
> @@ -4425,19 +4430,21 @@ static int hidpp_probe(struct hid_device
> *hdev, const struct hid_device_id *id)
>  
>         hidpp_connect_event(hidpp);
>  
> -       /* Reset the HID node state */
> -       hid_device_io_stop(hdev);
> -       hid_hw_close(hdev);
> -       hid_hw_stop(hdev);
> +       if (will_restart) {
> +               /* Reset the HID node state */
> +               hid_device_io_stop(hdev);
> +               hid_hw_close(hdev);
> +               hid_hw_stop(hdev);
>  
> -       if (hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT)
> -               connect_mask &= ~HID_CONNECT_HIDINPUT;
> +               if (hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT)
> +                       connect_mask &= ~HID_CONNECT_HIDINPUT;
>  
> -       /* Now export the actual inputs and hidraw nodes to the world
> */
> -       ret = hid_hw_start(hdev, connect_mask);
> -       if (ret) {
> -               hid_err(hdev, "%s:hid_hw_start returned error\n",
> __func__);
> -               goto hid_hw_start_fail;
> +               /* Now export the actual inputs and hidraw nodes to
> the world */
> +               ret = hid_hw_start(hdev, connect_mask);
> +               if (ret) {
> +                       hid_err(hdev, "%s:hid_hw_start returned
> error\n", __func__);
> +                       goto hid_hw_start_fail;
> +               }
>         }
>  
>         if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {