On Thu, Mar 21, 2013 at 06:13:17PM +0000, Stephen Boyd wrote: > On 03/21/13 11:09, Mark Rutland wrote: > > Hi Stephen, > > > > I've just been trying to test the dummy timer, and realised it's broken, as it > > registers a cpu notifier from a device_initcall (after SMP's been brought up), > > and doesn't ensure all active CPUs have been set up. Evidently no-one else has > > attempted to test it thus far, and I'm not able to throughly test it at the > > moment. > > Would it be sufficient to register as a pre-smp initcall? I've looked a bit further into the problem, and I believe using early_initcall will make it work as well as the current arm-specific dummy timers work with a rating of 100 (this means the recent patch lowering the rating broke tc2 as explained below). I've spent the last few hours trying to get the dummy_timer driver working on tc2 with the sp804 as the broadcast source (with architected timer support disabled). It turns out that having dummy timer's rating so low means that it won't be selected as the tick device on cpu0 in preference to the sp804, and thus won't push the sp804 out of that spot (allowing it to become the broadcast source). This leads to boot stalling. Jumping the dummy_timer's rating up would fix this, but that doesn't seem great. Registering the dummy before all other clocks would also fix this (I tried calling dummy_timer_register from time_init), but I can't see a way to do that while keeping the driver self-contained. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
