Messages in this thread | | | Date | Sat, 4 Oct 2008 21:43:41 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2] rfkill-input doesn't work until 5 minutes after boot |
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On Sun, 5 Oct 2008 01:43:34 +0100 Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> rfkill-input implements debounce as follows: > > if (time_after(jiffies, task->last + msecs_to_jiffies(200))) { > > However, task->last is initialised to 0 while jiffies starts at -300*HZ. > Any input within 5 minutes of kernel start is therefore ignored. Fix by > initialising task->last correctly. > > Signed-off-by: Matthew Garrett <mjg@redhat.com> > > --- > > Set the last event value at module load time, since otherwise we'll have > a window of failure if someone loads the module in a few hundred million > years. I look forward to being rewarded by the post-humans for caring so > much about them.
Jiffies wraparound is 49.7 days at HZ=1000.
> diff --git a/net/rfkill/rfkill-input.c b/net/rfkill/rfkill-input.c > index e5b6955..86197bb 100644 > --- a/net/rfkill/rfkill-input.c > +++ b/net/rfkill/rfkill-input.c > @@ -255,6 +255,11 @@ static struct input_handler rfkill_handler = { > > static int __init rfkill_handler_init(void) > { > + rfkill_wlan.last = jiffies - HZ/5; > + rfkill_bt.last = jiffies - HZ/5; > + rfkill_uwb.last = jiffies - HZ/5; > + rfkill_wimax.last = jiffies - HZ/5; > + rfkill_wwan.last = jiffies - HZ/5; > return input_register_handler(&rfkill_handler); > }
If someone adds a new rfkill_foo there's a risk that they'll forget to make the corresponding change here. A comment at the definition sites would help.
Or, better, do something like
static struct rfkill_task rfkill_tasks[] = { DEFINE_RFKILL_TASK(RFKILL_TYPE_WLAN), ... };
#define rfkill_wlan rfkill_tasks[0] ...
for (i = 0; i < ARRAY_SIZE(rfkill_tasks); i++) ...
but the new definition of DEFINE_RFKILL_TASK gets tricky.
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