Messages in this thread | | | Date | Wed, 2 Jun 2010 20:23:00 +1000 | From | Neil Brown <> | Subject | Re: [PATCH] - race-free suspend. Was: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) |
| |
On Wed, 2 Jun 2010 10:50:39 +0200 Florian Mickler <florian@mickler.org> wrote:
> On Wed, 2 Jun 2010 18:06:14 +1000 > Neil Brown <neilb@suse.de> wrote: > > > I cannot imagine why it would take multiple seconds to scan a keypad. > > Can you explain that? > > > > Do you mean while keys are held pressed? Maybe you don't get a wake-up event > > on key-release? In that case your user-space daemon could block suspend > > while there are any pressed keys.... confused. > > IIRC, the device sends interrupts only for first key-down and > last key-up. > To detect simultaneous key-presses you must actively scan it after the > first key-down.
That makes sense - thanks. Presumably the first key-press gets to user-space promptly, so the user-space suspend daemon can be told not to suspend until the last key-up.
Thanks, NeilBrown
| |