On Wed, Jan 24, 2018 at 10:38:22AM +0800, Jia-Ju Bai wrote: > The function apple_airport_reset is not called in atomic context. > Thus mdelay can be replaced with usleep_range, to avoid busy wait. > > This is reported by a static analysis tool named DCNS written by myself.
No, usleep_range() is built on hrtimers and at this point in the boot sequence we haven't called hrtimers_init() yet. Look at init/main.c:start_kernel() and note that setup_arch() (which calls early_quirks()) is called way before hrtimers_init(). Please amend your static checker to consider every call to mdelay() that occurs before hrtimers_init() a false positive, or manually verify each patch for this constraint before submission. I'll test your patch later today on my MacBook Pro but I suspect it'll cause a boot crash or hang. In any case the choice of mdelay() here was deliberate. Thanks, Lukas > > Signed-off-by: Jia-Ju Bai <[email protected]> > --- > arch/x86/kernel/early-quirks.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c > index 1e82f78..559e81a 100644 > --- a/arch/x86/kernel/early-quirks.c > +++ b/arch/x86/kernel/early-quirks.c > @@ -604,7 +604,7 @@ static void __init apple_airport_reset(int bus, int slot, > int func) > if ((pmcsr & PCI_PM_CTRL_STATE_MASK) != PCI_D0) { > pmcsr &= ~PCI_PM_CTRL_STATE_MASK; > write_pci_config_16(bus, slot, func, BCM4331_PM_CAP + > PCI_PM_CTRL, pmcsr); > - mdelay(10); > + usleep_range(10000, 11000); > > pmcsr = read_pci_config_16(bus, slot, func, BCM4331_PM_CAP + > PCI_PM_CTRL); > if ((pmcsr & PCI_PM_CTRL_STATE_MASK) != PCI_D0) { > -- > 1.7.9.5 >
