linux-kernel - Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux is running as dom0

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Date:	Mon, 15 Jul 2013 11:25:32 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Julien Grall <julien.grall@...aro.org>
Cc:	stefano.stabellini@...citrix.com, ian.campbell@...rix.com,
	patches@...aro.org, linux-kernel@...r.kernel.org,
	xen-devel@...ts.xen.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [Xen-devel] [PATCH] xen/arm: disable cpuidle when linux is
 running as dom0

On Mon, Jul 15, 2013 at 03:21:41PM +0100, Julien Grall wrote:
> When linux is running as dom0, Xen doesn't show the physical cpu but a
> virtual CPU.
> On some ARM SOC (for instance the exynos 5250), linux registers callbacks
> for cpuidle. When these callbacks are called, they will modify
> directly the physical cpu not the virtual one. It can impact the whole board
> instead of dom0.

Should you also call disable_cpufreq() ?

> 
> Signed-off-by: Julien Grall <julien.grall@...aro.org>
> ---
>  arch/arm/xen/enlighten.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 49839d8..a98999f 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -24,6 +24,8 @@
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_address.h>
> +#include <linux/cpuidle.h>
> +#include <linux/cpufreq.h>
>  
>  #include <linux/mm.h>
>  
> @@ -292,6 +294,11 @@ static int __init xen_pm_init(void)
>  {
>  	pm_power_off = xen_power_off;
>  	arm_pm_restart = xen_restart;
> +	/*
> +	 * Making sure board specific code will not set up ops for
> +	 * cpu idle.
> +	 */
> +	disable_cpuidle();
>  
>  	return 0;
>  }
> -- 
> 1.7.10.4
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xen.org
> http://lists.xen.org/xen-devel
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