Re: Enable arm_global_timer for Zynq brakes boot

[Daniel Lezcano]

On 07/30/2013 02:03 AM, SÃren Brinkmann wrote:
> Hi Daniel,
> 
> On Mon, Jul 29, 2013 at 02:51:49PM +0200, Daniel Lezcano wrote:
> (snip)
>>
>> the CPUIDLE_FLAG_TIMER_STOP flag tells the cpuidle framework the local
>> timer will be stopped when entering to the idle state. In this case, the
>> cpuidle framework will call clockevents_notify(ENTER) and switches to a
>> broadcast timer and will call clockevents_notify(EXIT) when exiting the
>> idle state, switching the local timer back in use.
> 
> I've been thinking about this, trying to understand how this makes my
> boot attempts on Zynq hang. IIUC, the wrongly provided TIMER_STOP flag
> would make the timer core switch to a broadcast device even though it
> wouldn't be necessary. But shouldn't it still work? It sounds like we do
> something useless, but nothing wrong in a sense that it should result in
> breakage. I guess I'm missing something obvious. This timer system will
> always remain a mystery to me.
> 
> Actually this more or less leads to the question: What is this
> 'broadcast timer'. I guess that is some clockevent device which is
> common to all cores? (that would be the cadence_ttc for Zynq). Is the
> hang pointing to some issue with that driver?

If you look at the /proc/timer_list, which timer is used for broadcasting ?

-- 
 <http://www.linaro.org/> Linaro.org â Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/