Enable arm_global_timer for Zynq brakes boot
soren.brinkmann at xilinx.com
Mon Aug 12 12:53:49 EDT 2013
On Mon, Aug 12, 2013 at 06:49:17PM +0200, Daniel Lezcano wrote:
> On 08/12/2013 06:32 PM, Sören Brinkmann wrote:
> > On Mon, Aug 12, 2013 at 09:20:19AM -0700, Stephen Boyd wrote:
> >> On 08/12/13 09:03, Sören Brinkmann wrote:
> >>> On Fri, Aug 09, 2013 at 10:27:57AM -0700, Stephen Boyd wrote:
> >>>> On 08/09, Daniel Lezcano wrote:
> >>>>> yes, but at least the broadcast mechanism should send an IPI to cpu0 to
> >>>>> wake it up, no ? As Stephen stated this kind of configuration should has
> >>>>> never been tested before so the tick broadcast code is not handling this
> >>>>> case properly IMHO.
> >>>> If you have a per-cpu tick device that isn't suffering from
> >>>> FEAT_C3_STOP why wouldn't you use that for the tick versus a
> >>>> per-cpu tick device that has FEAT_C3_STOP? It sounds like there
> >>>> is a bug in the preference logic or you should boost the rating
> >>>> of the arm global timer above the twd. Does this patch help? It
> >>>> should make the arm global timer the tick device and whatever the
> >>>> cadence timer you have into the broadcast device.
> >>> I finally got to test your patch. Unfortunately, it makes the system
> >>> hang even earlier:
> >> Sorry it had a bug depending on the registration order. Can you try this
> >> one (tabs are probably spaces, sorry)? I will go read through this
> >> thread to see if we already covered the registration order.
> > That did it! Booted straight into the system.
> Good news :)
> > The broadcast device is
> > the TTC instead of GT, now.
> > Tick Device: mode: 1
> > Broadcast device
> > Clock Event Device: ttc_clockevent
> > max_delta_ns: 1207932479
> > min_delta_ns: 18432
> > mult: 233015
> > shift: 32
> > mode: 1
> > next_event: 9223372036854775807 nsecs
> > set_next_event: ttc_set_next_event
> > set_mode: ttc_set_mode
> > event_handler: tick_handle_oneshot_broadcast
> > retries: 0
> > tick_broadcast_mask: 00000000
> > tick_broadcast_oneshot_mask: 00000000
> At the first glance, the timer broadcast usage is not set, right ? Can
> you try with the cpuidle flag even if it is not needed ?
It's actually present. I have a clean 3.11-rc3 and the only changes are
my patch to enable the GT and Stephen's fix.
The cpuidle stats show both idle states being used.
More information about the linux-arm-kernel