Re: [RFC PATCH] Bluetooth: btnxpuart: Fix nxp_setup in case chip is powered on late

Neeraj Sanjay Kale
2024-01-17T09:38:46Z

Hi Francesco,

Thankyou for the review comment.

> > diff --git a/drivers/bluetooth/btnxpuart.c
> > b/drivers/bluetooth/btnxpuart.c index 7f88b6f52f26..20a3a5bd5529
> > 100644
> > --- a/drivers/bluetooth/btnxpuart.c
> > +++ b/drivers/bluetooth/btnxpuart.c
> > @@ -1036,6 +1048,13 @@ static int nxp_setup(struct hci_dev *hdev)
> > err = nxp_download_firmware(hdev);
> > if (err < 0)
> > return err;
> > + } else if (!serdev_device_get_cts(nxpdev->serdev)) {
> > + /* CTS is high and no bootloader signatures detected */
> > + bt_dev_dbg(hdev, "Controller not detected. Will check again in %d
> msec",
> > + NXP_SETUP_RETRY_TIME_MS);
> > + schedule_delayed_work(&nxpdev->setup_retry_work,
> > + msecs_to_jiffies(NXP_SETUP_RETRY_TIME_MS));
> > + return -ENODEV;
> why not just
>
> return -EPROBE_DEFER;
>
> and remove everything else, no need for any kind of retry or delayed work if
> the driver core takes care of it.
>
Wouldn't returning -EPROBE_DEFER make more sense in driver probe context?

Here, the driver probe registers an hci interface (hci_register_dev()), and returns success to kernel.

The hci_register_dev() queues hdev->power_on work at the end, which opens the hci dev, and ultimately calls this setup function.

In this patch, we are queueing the same work from the delayed setup_retry_work().

Returning -ENODEV (or -EPROBE_DEFER) would only affect hci_dev_open(), which is in power_on work context, and not driver probe context.

Perhaps, we should call it hci_retry_power_on() work or something similar?

Please let me know your thoughts on this.

Thanks,
Neeraj