RE: Question about a freeze under Xenomai 3.2.1

["Schuman Eelco (DC-AE/ESW5)" <Eelco.Schuman@boschrexroth.nl>]

Hi,

>With your suggestions I finally had a working setup with SMP:

>The culprit shown itself when I printed the original timer that is 
>proxied by the timer_proxy,

>On the non-SMP kernel the timer is set to "arm_global_timer", while on SMP it was set to "local_timer" :


> From what I understood, there is one timer per CPU , while the 
>arm_global_timer is global to the system.

>Digging a little more, I found out that the local_timer was implemented 
>by the "scutimer" on the zynq7000 platform.
>As a first approach, I just disabled this timer in the DTS.
>
>With that the proxy original clock is now arm_glocal_timer for both CPU 
>and it work.

>However.... I have a bad feeling about this, it look like I did not go 
>down to the real issue which is that the scutimer does not generate 
>timer events as it should.

I disabled only the generation of clockevents for the default timer ( arch/arm/kernel/smp_twd.c ). Both timers are running but the global timer is now used for the clockevents. I'm not sure if this is the best solution or  if it has an impact on performance. 

static void twd_timer_setup(void)
{
	struct clock_event_device *clk = raw_cpu_ptr(twd_evt);
	int cpu = smp_processor_id();
...
...
	//clockevents_config_and_register(clk, twd_timer_rate,                do not use this timer for clockevents
	//				0xf, 0xffffffff);
	enable_percpu_irq(clk->irq, 0);
}

This is with linux-v5.10.153-dovetail1.

Eelco Schuman