• Lukas Wunner's avatar
    Bluetooth: hci_bcm: Sleep instead of spinning · e4b9e5b8
    Lukas Wunner authored
    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, 118612fb ("Bluetooth: hci_bcm: Add
    suspend/resume PM functions"), does not provide a rationale.
    
    Cc: Frédéric Danis <frederic.danis.oss@gmail.com>
    Suggested-and-reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
    Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
    Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
    e4b9e5b8
hci_bcm.c 28.3 KB