Return-Path: Message-Id: In-Reply-To: References: From: Lukas Wunner Date: Sun, 7 Jan 2018 20:16:32 +0100 Subject: [PATCH v3 12/13] Bluetooth: hci_bcm: Sleep instead of spinning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 To: Marcel Holtmann , Johan Hedberg Cc: Mika Westerberg , Andy Shevchenko , Frederic Danis , Loic Poulain , Hans de Goede , Max Shavrick , Leif Liddy , Daniel Roschka , Ronald Tschalaer , "Peter Y. Chuang" , linux-bluetooth@vger.kernel.org List-ID: 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-by: Andy Shevchenko Signed-off-by: Lukas Wunner --- drivers/bluetooth/hci_bcm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c index 5252b3ef5ad4..81e82ce2da96 100644 --- a/drivers/bluetooth/hci_bcm.c +++ b/drivers/bluetooth/hci_bcm.c @@ -657,7 +657,7 @@ static int bcm_suspend_device(struct device *dev) } bt_dev_dbg(bdev, "suspend, delaying 15 ms"); - mdelay(15); + msleep(15); return 0; } @@ -676,7 +676,7 @@ 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) { -- 2.15.1