linux-kernel - Re: [BUG?] Interrupts enabled after xen_acpi_processor_resume+0x0/0x34 [xen_acpi

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Message-ID: <20140203141429.GD3400@phenom.dumpdata.com>
Date:	Mon, 3 Feb 2014 09:14:29 -0500
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Stanislaw Gruszka <sgruszka@...hat.com>
Cc:	David Rientjes <rientjes@...gle.com>, boris.ostrovsky@...cle.com,
	david.vrabel@...rix.com, Ben Guthro <benjamin.guthro@...rix.com>,
	linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	xen-devel@...ts.xensource.com
Subject: Re: [BUG?] Interrupts enabled after
 xen_acpi_processor_resume+0x0/0x34 [xen_acpi_processor]

On Mon, Feb 03, 2014 at 11:12:16AM +0100, Stanislaw Gruszka wrote:
> On Fri, Jan 31, 2014 at 11:01:40AM -0500, Konrad Rzeszutek Wilk wrote:
> > Perhaps by using 'subsys_system_register' and stick it there?
> 
> This will not call ->resume callback as it is only called for
> devices, so additional dummy device is needed, for example:
> 
> struct device xap_dev = {
>         .init_name = "xen-acpi-processor-dev",
>         .bus = &xap_bus,
> };
> ...
> subsys_system_register(&xap_bus, NULL);
> device_register(&xap_dev);
> 
> But I'm not sure if that is good solution. It crate some not necessery
> sysfs directories and files. Additionaly it can restore CPU C-states
> after some other drivers resume, which prehaps require proper C-states.

Yes.
> 
> Hence maybe adding direct notify from xen core resume will be better
> idea (proposed patch below). Plese let me know what you think, I'll
> provide solution which you choose to bug reporters for testing.

Let me think about it for a day or so.

Thanks!
> 
> Thanks
> Stanislaw
> 
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index 624e8dc..96e4173 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -13,6 +13,7 @@
>  #include <linux/freezer.h>
>  #include <linux/syscore_ops.h>
>  #include <linux/export.h>
> +#include <linux/notifier.h>
>  
>  #include <xen/xen.h>
>  #include <xen/xenbus.h>
> @@ -46,6 +47,20 @@ struct suspend_info {
>  	void (*post)(int cancelled);
>  };
>  
> +static RAW_NOTIFIER_HEAD(xen_resume_notifier);
> +
> +void xen_resume_notifier_register(struct notifier_block *nb)
> +{
> +	raw_notifier_chain_register(&xen_resume_notifier, nb);
> +}
> +EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
> +
> +void xen_resume_notifier_unregister(struct notifier_block *nb)
> +{
> +	raw_notifier_chain_unregister(&xen_resume_notifier, nb);
> +}
> +EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
> +
>  #ifdef CONFIG_HIBERNATE_CALLBACKS
>  static void xen_hvm_post_suspend(int cancelled)
>  {
> @@ -152,6 +167,8 @@ static void do_suspend(void)
>  
>  	err = stop_machine(xen_suspend, &si, cpumask_of(0));
>  
> +	raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
> +
>  	dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
>  
>  	if (err) {
> diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
> index 7231859..82358d1 100644
> --- a/drivers/xen/xen-acpi-processor.c
> +++ b/drivers/xen/xen-acpi-processor.c
> @@ -27,10 +27,10 @@
>  #include <linux/init.h>
>  #include <linux/module.h>
>  #include <linux/types.h>
> -#include <linux/syscore_ops.h>
>  #include <linux/acpi.h>
>  #include <acpi/processor.h>
>  #include <xen/xen.h>
> +#include <xen/xen-ops.h>
>  #include <xen/interface/platform.h>
>  #include <asm/xen/hypercall.h>
>  
> @@ -495,14 +495,15 @@ static int xen_upload_processor_pm_data(void)
>  	return rc;
>  }
>  
> -static void xen_acpi_processor_resume(void)
> +static int xen_acpi_processor_resume(struct notifier_block *nb,
> +				     unsigned long action, void *data)
>  {
>  	bitmap_zero(acpi_ids_done, nr_acpi_bits);
> -	xen_upload_processor_pm_data();
> +	return xen_upload_processor_pm_data();
>  }
>  
> -static struct syscore_ops xap_syscore_ops = {
> -	.resume	= xen_acpi_processor_resume,
> +struct notifier_block xen_acpi_processor_resume_nb = {
> +	.notifier_call = xen_acpi_processor_resume,
>  };
>  
>  static int __init xen_acpi_processor_init(void)
> @@ -555,7 +556,7 @@ static int __init xen_acpi_processor_init(void)
>  	if (rc)
>  		goto err_unregister;
>  
> -	register_syscore_ops(&xap_syscore_ops);
> +	xen_resume_notifier_register(&xen_acpi_processor_resume_nb);
>  
>  	return 0;
>  err_unregister:
> @@ -574,7 +575,7 @@ static void __exit xen_acpi_processor_exit(void)
>  {
>  	int i;
>  
> -	unregister_syscore_ops(&xap_syscore_ops);
> +	xen_resume_notifier_unregister(&xen_acpi_processor_resume_nb);
>  	kfree(acpi_ids_done);
>  	kfree(acpi_id_present);
>  	kfree(acpi_id_cst_present);
> diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
> index fb2ea8f..6412358 100644
> --- a/include/xen/xen-ops.h
> +++ b/include/xen/xen-ops.h
> @@ -16,6 +16,9 @@ void xen_mm_unpin_all(void);
>  void xen_timer_resume(void);
>  void xen_arch_resume(void);
>  
> +void xen_resume_notifier_register(struct notifier_block *nb);
> +void xen_resume_notifier_unregister(struct notifier_block *nb);
> +
>  int xen_setup_shutdown_event(void);
>  
>  extern unsigned long *xen_contiguous_bitmap;
--
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