On Sat, Aug 25, 2012 at 11:25:26AM +0200, David Härdeman wrote: > On Sat, Aug 25, 2012 at 12:26:25AM +0100, Sean Young wrote: > >On Sat, Aug 25, 2012 at 12:05:18AM +0200, David Härdeman wrote: > >> On Thu, Aug 23, 2012 at 10:18:35PM +0100, Sean Young wrote: > >> >Some drivers wait for the IR device to complete sending before > >> >returning, so sleeping should not be done. > >> > >> I'm not quite sure what the purpose is. Even if a driver waits for TX to > >> finish, the lirc imposed sleep isn't harmful in any way. > > > >Due to rounding errors, clock skew and different start times, the sleep > >might be waiting for a different amount of time than the hardware took > >to send it. The sleep is a bit of a kludge, let alone if the driver > >can wait for the hardware to tell you when it's done. > > I don't see the sleep as much of a problem right now. Whether the > hardware says its done or if we simulate the same thing in the lirc > layer, the entire concept is a bit of a kludge :) It's not making it any better. > >Also, your change calculates the amount of us to sleep after transmission, > >so if the transmission buffer was modified by the driver, the calculated > >sleep might not make sense. Both winbond-cir and iguanair do this. > > Oh, right, I'd overlooked this. I have written patches for winbond-cir > (which makes it asynchronous and leaves the txbuffer alone) and iguanair > (to leave the txbuffer alone). I'll post them sometime today when I've > done some more tests. If this is the solution we're going for, then I've got a patch for iguanair which leaves the txbuffer alone and is ready and tested. I'll send it out in the next half hour. Sean -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
