From: Lukas Wunner Date: Wed, 10 Jan 2018 15:32:10 +0000 (+0100) Subject: Bluetooth: hci_bcm: Sleep instead of spinning X-Git-Tag: v4.19~1702^2~177^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e4b9e5b8618dc59f5de5cecf4e0188a3cdcd5648;p=platform%2Fkernel%2Flinux-rpi.git Bluetooth: hci_bcm: Sleep instead of spinning The driver calls mdelay(15) in the ->suspend, ->resume, ->runtime_suspend and ->runtime_resume hook, however spinning for such a long period of time is discouraged as per Documentation/timers/timers-howto.txt. The use of mdelay() seems unnecessary, it is allowed to sleep in the system sleep and runtime PM hooks (with the exception of ->suspend_noirq and ->resume_noirq) and the driver itself also does not rely on a non-sleeping ->runtime_resume as the only place where a synchronous resume is performed, in bcm_dequeue(), is called from a work item in hci_ldisc.c and hci_serdev.c. So replace the mdelay(15) with msleep(15). Note that the delay is inserted after asserting or deasserting the device wake pin, but in bcm_gpio_set_power() that pin is asserted or deasserted *without* observing a delay. It is thus unclear if the delay is necessary at all. It is likewise unclear why it is exactly 15 ms, the commit introducing it, 118612fb9165 ("Bluetooth: hci_bcm: Add suspend/resume PM functions"), does not provide a rationale. Cc: Frédéric Danis Suggested-and-reviewed-by: Andy Shevchenko Signed-off-by: Lukas Wunner Signed-off-by: Marcel Holtmann --- diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c index 0929a26..461364a 100644 --- a/drivers/bluetooth/hci_bcm.c +++ b/drivers/bluetooth/hci_bcm.c @@ -656,7 +656,7 @@ static int bcm_suspend_device(struct device *dev) } bt_dev_dbg(bdev, "suspend, delaying 15 ms"); - mdelay(15); + msleep(15); return 0; } @@ -675,7 +675,7 @@ static int bcm_resume_device(struct device *dev) } bt_dev_dbg(bdev, "resume, delaying 15 ms"); - mdelay(15); + msleep(15); /* When this executes, the device has woken up already */ if (bdev->is_suspended && bdev->hu) {