ACPI: Enable SCI_EMULATE to manually simulate physical hotplug testing.

Commit Message

Yinghai Lu Sept. 3, 2012, 9:27 p.m. UTC

From: Ashok Raj <[e-mail]>

Emulate an ACPI SCI interrupt to emulate a hot-plug event. Useful
for testing ACPI based hot-plug on systems that don't have the
necessary firmware support.

Enable CONFIG_ACPI_SCI_EMULATE on kernel compile.

Now you will notice /sys/kernel/debug/acpi/sci_notify when new kernel is
booted.

echo "\_SB.PCIB 1" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-add
of root bus that is corresponding to PCIB.

echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-remove
of root bus that is corresponding to PCIB.

-v2: Update to current upstream, and remove not related stuff.
-v3: According to Len's request, update it to use debugfs.  - Yinghai Lu

Signed-off-by: Yinghai Lu <[e-mail]>
Cc: Len Brown <[e-mail]>
Cc: [e-mail]

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Comments

Toshi Kani Sept. 4, 2012, 4:27 p.m. UTC | #1

On Mon, 2012-09-03 at 14:27 -0700, Yinghai Lu wrote:
> From: Ashok Raj <[e-mail]>
> 
> Emulate an ACPI SCI interrupt to emulate a hot-plug event. Useful
> for testing ACPI based hot-plug on systems that don't have the
> necessary firmware support.
> 
> Enable CONFIG_ACPI_SCI_EMULATE on kernel compile.
> 
> Now you will notice /sys/kernel/debug/acpi/sci_notify when new kernel is
> booted.
> 
> echo "\_SB.PCIB 1" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-add
> of root bus that is corresponding to PCIB.
> 
> echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-remove
> of root bus that is corresponding to PCIB.

Hi Yinghai,

This feature has been very useful.  Thanks for working on this change.
I have a few comments below.


> -v2: Update to current upstream, and remove not related stuff.
> -v3: According to Len's request, update it to use debugfs.  - Yinghai Lu
> 
> Signed-off-by: Yinghai Lu <[e-mail]>
> Cc: Len Brown <[e-mail]>
> Cc: [e-mail]
> 
> ===================================================================
> ---
>  drivers/acpi/Kconfig   |   10 +++
>  drivers/acpi/Makefile  |    1 
>  drivers/acpi/sci_emu.c |  145 +++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 156 insertions(+)
> 
> Index: linux-2.6/drivers/acpi/Kconfig
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/Kconfig
> +++ linux-2.6/drivers/acpi/Kconfig
> @@ -272,6 +272,16 @@ config ACPI_BLACKLIST_YEAR
>  	  Enter 0 to disable this mechanism and allow ACPI to
>  	  run by default no matter what the year.  (default)
>  
> +config ACPI_SCI_EMULATE
> +        bool "ACPI SCI Event Emulation Support"
> +        depends on DEBUG_FS
> +	default n
> +	help
> +	  This will enable your system to emulate sci hotplug event
> +	  notification through proc file system. For example user needs to
> +	  echo "XXX 0" > /sys/kernel/debug/acpi/sci_notify (where, XXX is
> +	  a target ACPI device object name present under \_SB scope).
> +
>  config ACPI_DEBUG
>  	bool "Debug Statements"
>  	default n
> Index: linux-2.6/drivers/acpi/sci_emu.c
> ===================================================================
> --- /dev/null
> +++ linux-2.6/drivers/acpi/sci_emu.c
> @@ -0,0 +1,145 @@
> +/*
> + *  Code to emulate SCI interrupt for Hotplug node insertion/removal
> + */
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/uaccess.h>
> +#include <linux/debugfs.h>
> +#include <acpi/acpi_drivers.h>
> +
> +#include "internal.h"
> +
> +#include "acpica/accommon.h"
> +#include "acpica/acnamesp.h"
> +#include "acpica/acevents.h"
> +
> +#define _COMPONENT		ACPI_SYSTEM_COMPONENT
> +ACPI_MODULE_NAME("sci_emu");
> +MODULE_LICENSE("GPL");
> +
> +static struct dentry *sci_notify_dentry;
> +
> +static void sci_notify_client(char *acpi_name, u32 event)
> +{
> +	struct acpi_namespace_node *node;
> +	acpi_status status, status1;
> +	acpi_handle hlsb, hsb;
> +	union acpi_operand_object *obj_desc;
> +
> +	status = acpi_get_handle(NULL, "\\_SB", &hsb);
> +	status1 = acpi_get_handle(hsb, acpi_name, &hlsb);

Why do you obtain hsb for \_SB when acpi_name is supposed to be a full
path name?  Can you simply specify a NULL like this?
  status = acpi_get_handle(NULL, acpi_name, &hlsb);


> +	if (ACPI_FAILURE(status) || ACPI_FAILURE(status1)) {
> +		pr_err(PREFIX
> +	"acpi getting handle to <\\_SB.%s> failed inside notify_client\n",
> +			acpi_name);
> +		return;
> +	}
> +
> +	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
> +	if (ACPI_FAILURE(status)) {
> +		pr_err(PREFIX "Acquiring acpi namespace mutext failed\n");
> +		return;
> +	}
> +
> +	node = acpi_ns_validate_handle(hlsb);
> +	if (!node) {
> +		acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
> +		pr_err(PREFIX "Mapping handle to node failed\n");
> +		return;
> +	}
> +
> +	/*
> +	 * Check for internal object and make sure there is a handler
> +	 * registered for this object
> +	 */
> +	obj_desc = acpi_ns_get_attached_object(node);
> +	if (obj_desc) {
> +		if (obj_desc->common_notify.notify_list[0]) {

Is the above check necessary?  acpi_ev_queue_notify_request() sets up to
call the global handler, acpi_gbl_global_notify[0], even if the object
does not have a local handler registered.

Thanks,
-Toshi


> +			/*
> +			 * Release the lock and queue the item for later
> +			 * exectuion
> +			 */
> +			acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
> +			status = acpi_ev_queue_notify_request(node, event);
> +			if (ACPI_FAILURE(status))
> +				pr_err(PREFIX "acpi_ev_queue_notify_request failed\n");
> +			else
> +				pr_info(PREFIX "Notify event is queued\n");
> +			return;
> +		}
> +	} else {
> +		pr_info(PREFIX "Notify handler not registered for this device\n");
> +	}
> +
> +	acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
> +	return;
> +}
> +
> +static ssize_t sci_notify_write(struct file *file, const char __user *user_buf,
> +				 size_t count, loff_t *ppos)
> +{
> +	u32 event;
> +	char *name1 = NULL;
> +	char *name2 = NULL;
> +	const char *delim = " ";
> +	char *temp_buf = NULL;
> +	char *temp_buf_addr = NULL;
> +
> +	temp_buf = kmalloc(count+1, GFP_ATOMIC);
> +	if (!temp_buf) {
> +		pr_warn(PREFIX "sci_notify_wire: Memory allocation failed\n");
> +		return count;
> +	}
> +	temp_buf[count] = '\0';
> +	temp_buf_addr = temp_buf;
> +	if (copy_from_user(temp_buf, user_buf, count))
> +		goto out;
> +
> +	name1 = strsep(&temp_buf, delim);
> +	name2 = strsep(&temp_buf, delim);
> +
> +	if (name1 && name2) {
> +		ssize_t ret;
> +		unsigned long val;
> +
> +		ret = kstrtoul(name2, 10, &val);
> +		if (ret) {
> +			pr_warn(PREFIX "unknown event\n");
> +			goto out;
> +		}
> +
> +		event = (u32)val;
> +	} else {
> +		pr_warn(PREFIX "unknown device\n");
> +		goto out;
> +	}
> +
> +	pr_info(PREFIX "ACPI device name is <%s>, event code is <%d>\n",
> +		name1, event);
> +
> +	sci_notify_client(name1, event);
> +
> +out:
> +	kfree(temp_buf_addr);
> +	return count;
> +}
> +
> +static const struct file_operations sci_notify_fops = {
> +	.write = sci_notify_write,
> +};
> +
> +static int __init acpi_sci_notify_init(void)
> +{
> +	if (acpi_debugfs_dir == NULL)
> +		return -ENOENT;
> +
> +	sci_notify_dentry = debugfs_create_file("sci_notify", S_IWUSR,
> +				acpi_debugfs_dir, NULL, &sci_notify_fops);
> +	if (sci_notify_dentry == NULL)
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +
> +device_initcall(acpi_sci_notify_init);
> Index: linux-2.6/drivers/acpi/Makefile
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/Makefile
> +++ linux-2.6/drivers/acpi/Makefile
> @@ -31,6 +31,7 @@ acpi-$(CONFIG_ACPI_SLEEP)	+= proc.o
>  # ACPI Bus and Device Drivers
>  #
>  acpi-y				+= bus.o glue.o
> +acpi-$(CONFIG_ACPI_SCI_EMULATE)	+= sci_emu.o
>  acpi-y				+= scan.o
>  acpi-y				+= processor_core.o
>  acpi-y				+= ec.o
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Yinghai Lu Sept. 4, 2012, 7:17 p.m. UTC | #2

On Tue, Sep 4, 2012 at 9:27 AM, Toshi Kani <[e-mail]> wrote:
> On Mon, 2012-09-03 at 14:27 -0700, Yinghai Lu wrote:
>> From: Ashok Raj <[e-mail]>
>>
>> Emulate an ACPI SCI interrupt to emulate a hot-plug event. Useful
>> for testing ACPI based hot-plug on systems that don't have the
>> necessary firmware support.
>>
>> Enable CONFIG_ACPI_SCI_EMULATE on kernel compile.
>>
>> Now you will notice /sys/kernel/debug/acpi/sci_notify when new kernel is
>> booted.
>>
>> echo "\_SB.PCIB 1" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-add
>> of root bus that is corresponding to PCIB.
>>
>> echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-remove
>> of root bus that is corresponding to PCIB.
>
> Hi Yinghai,
>
> This feature has been very useful.  Thanks for working on this change.
> I have a few comments below.
>
>
>> -v2: Update to current upstream, and remove not related stuff.
>> -v3: According to Len's request, update it to use debugfs.  - Yinghai Lu
>>
>> Signed-off-by: Yinghai Lu <[e-mail]>
>> Cc: Len Brown <[e-mail]>
>> Cc: [e-mail]
>>
>> ===================================================================
>> ---
>>  drivers/acpi/Kconfig   |   10 +++
>>  drivers/acpi/Makefile  |    1
>>  drivers/acpi/sci_emu.c |  145 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 156 insertions(+)
>>
>> Index: linux-2.6/drivers/acpi/Kconfig
>> ===================================================================
>> --- linux-2.6.orig/drivers/acpi/Kconfig
>> +++ linux-2.6/drivers/acpi/Kconfig
>> @@ -272,6 +272,16 @@ config ACPI_BLACKLIST_YEAR
>>         Enter 0 to disable this mechanism and allow ACPI to
>>         run by default no matter what the year.  (default)
>>
>> +config ACPI_SCI_EMULATE
>> +        bool "ACPI SCI Event Emulation Support"
>> +        depends on DEBUG_FS
>> +     default n
>> +     help
>> +       This will enable your system to emulate sci hotplug event
>> +       notification through proc file system. For example user needs to
>> +       echo "XXX 0" > /sys/kernel/debug/acpi/sci_notify (where, XXX is
>> +       a target ACPI device object name present under \_SB scope).
>> +
>>  config ACPI_DEBUG
>>       bool "Debug Statements"
>>       default n
>> Index: linux-2.6/drivers/acpi/sci_emu.c
>> ===================================================================
>> --- /dev/null
>> +++ linux-2.6/drivers/acpi/sci_emu.c
>> @@ -0,0 +1,145 @@
>> +/*
>> + *  Code to emulate SCI interrupt for Hotplug node insertion/removal
>> + */
>> +#include <linux/init.h>
>> +#include <linux/module.h>
>> +#include <linux/kernel.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/debugfs.h>
>> +#include <acpi/acpi_drivers.h>
>> +
>> +#include "internal.h"
>> +
>> +#include "acpica/accommon.h"
>> +#include "acpica/acnamesp.h"
>> +#include "acpica/acevents.h"
>> +
>> +#define _COMPONENT           ACPI_SYSTEM_COMPONENT
>> +ACPI_MODULE_NAME("sci_emu");
>> +MODULE_LICENSE("GPL");
>> +
>> +static struct dentry *sci_notify_dentry;
>> +
>> +static void sci_notify_client(char *acpi_name, u32 event)
>> +{
>> +     struct acpi_namespace_node *node;
>> +     acpi_status status, status1;
>> +     acpi_handle hlsb, hsb;
>> +     union acpi_operand_object *obj_desc;
>> +
>> +     status = acpi_get_handle(NULL, "\\_SB", &hsb);
>> +     status1 = acpi_get_handle(hsb, acpi_name, &hlsb);
>
> Why do you obtain hsb for \_SB when acpi_name is supposed to be a full
> path name?  Can you simply specify a NULL like this?
>   status = acpi_get_handle(NULL, acpi_name, &hlsb);

assume those two main function is from ashok.

but assume that could make user omit \_SB_?

>
>
>> +     if (ACPI_FAILURE(status) || ACPI_FAILURE(status1)) {
>> +             pr_err(PREFIX
>> +     "acpi getting handle to <\\_SB.%s> failed inside notify_client\n",
>> +                     acpi_name);
>> +             return;
>> +     }
>> +
>> +     status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
>> +     if (ACPI_FAILURE(status)) {
>> +             pr_err(PREFIX "Acquiring acpi namespace mutext failed\n");
>> +             return;
>> +     }
>> +
>> +     node = acpi_ns_validate_handle(hlsb);
>> +     if (!node) {
>> +             acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
>> +             pr_err(PREFIX "Mapping handle to node failed\n");
>> +             return;
>> +     }
>> +
>> +     /*
>> +      * Check for internal object and make sure there is a handler
>> +      * registered for this object
>> +      */
>> +     obj_desc = acpi_ns_get_attached_object(node);
>> +     if (obj_desc) {
>> +             if (obj_desc->common_notify.notify_list[0]) {
>
> Is the above check necessary?  acpi_ev_queue_notify_request() sets up to
> call the global handler, acpi_gbl_global_notify[0], even if the object
> does not have a local handler registered.

Not sure.

maybe Len or other acpi guyes could answer your questions.

Thanks

Yinghai Lu
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Toshi Kani Sept. 4, 2012, 9:34 p.m. UTC | #3

On Tue, 2012-09-04 at 12:17 -0700, Yinghai Lu wrote:
> On Tue, Sep 4, 2012 at 9:27 AM, Toshi Kani <[e-mail]> wrote:
> > On Mon, 2012-09-03 at 14:27 -0700, Yinghai Lu wrote:
> >> From: Ashok Raj <[e-mail]>
> >>
> >> Emulate an ACPI SCI interrupt to emulate a hot-plug event. Useful
> >> for testing ACPI based hot-plug on systems that don't have the
> >> necessary firmware support.
> >>
> >> Enable CONFIG_ACPI_SCI_EMULATE on kernel compile.
> >>
> >> Now you will notice /sys/kernel/debug/acpi/sci_notify when new kernel is
> >> booted.
> >>
> >> echo "\_SB.PCIB 1" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-add
> >> of root bus that is corresponding to PCIB.
> >>
> >> echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify to trigger a hot-remove
> >> of root bus that is corresponding to PCIB.
> >
> > Hi Yinghai,
> >
> > This feature has been very useful.  Thanks for working on this change.
> > I have a few comments below.
> >
> >
> >> -v2: Update to current upstream, and remove not related stuff.
> >> -v3: According to Len's request, update it to use debugfs.  - Yinghai Lu
> >>
> >> Signed-off-by: Yinghai Lu <[e-mail]>
> >> Cc: Len Brown <[e-mail]>
> >> Cc: [e-mail]
> >>
> >> ===================================================================
> >> ---
> >>  drivers/acpi/Kconfig   |   10 +++
> >>  drivers/acpi/Makefile  |    1
> >>  drivers/acpi/sci_emu.c |  145 +++++++++++++++++++++++++++++++++++++++++++++++++
> >>  3 files changed, 156 insertions(+)
> >>
> >> Index: linux-2.6/drivers/acpi/Kconfig
> >> ===================================================================
> >> --- linux-2.6.orig/drivers/acpi/Kconfig
> >> +++ linux-2.6/drivers/acpi/Kconfig
> >> @@ -272,6 +272,16 @@ config ACPI_BLACKLIST_YEAR
> >>         Enter 0 to disable this mechanism and allow ACPI to
> >>         run by default no matter what the year.  (default)
> >>
> >> +config ACPI_SCI_EMULATE
> >> +        bool "ACPI SCI Event Emulation Support"
> >> +        depends on DEBUG_FS
> >> +     default n
> >> +     help
> >> +       This will enable your system to emulate sci hotplug event
> >> +       notification through proc file system. For example user needs to
> >> +       echo "XXX 0" > /sys/kernel/debug/acpi/sci_notify (where, XXX is
> >> +       a target ACPI device object name present under \_SB scope).
> >> +
> >>  config ACPI_DEBUG
> >>       bool "Debug Statements"
> >>       default n
> >> Index: linux-2.6/drivers/acpi/sci_emu.c
> >> ===================================================================
> >> --- /dev/null
> >> +++ linux-2.6/drivers/acpi/sci_emu.c
> >> @@ -0,0 +1,145 @@
> >> +/*
> >> + *  Code to emulate SCI interrupt for Hotplug node insertion/removal
> >> + */
> >> +#include <linux/init.h>
> >> +#include <linux/module.h>
> >> +#include <linux/kernel.h>
> >> +#include <linux/uaccess.h>
> >> +#include <linux/debugfs.h>
> >> +#include <acpi/acpi_drivers.h>
> >> +
> >> +#include "internal.h"
> >> +
> >> +#include "acpica/accommon.h"
> >> +#include "acpica/acnamesp.h"
> >> +#include "acpica/acevents.h"
> >> +
> >> +#define _COMPONENT           ACPI_SYSTEM_COMPONENT
> >> +ACPI_MODULE_NAME("sci_emu");
> >> +MODULE_LICENSE("GPL");
> >> +
> >> +static struct dentry *sci_notify_dentry;
> >> +
> >> +static void sci_notify_client(char *acpi_name, u32 event)
> >> +{
> >> +     struct acpi_namespace_node *node;
> >> +     acpi_status status, status1;
> >> +     acpi_handle hlsb, hsb;
> >> +     union acpi_operand_object *obj_desc;
> >> +
> >> +     status = acpi_get_handle(NULL, "\\_SB", &hsb);
> >> +     status1 = acpi_get_handle(hsb, acpi_name, &hlsb);
> >
> > Why do you obtain hsb for \_SB when acpi_name is supposed to be a full
> > path name?  Can you simply specify a NULL like this?
> >   status = acpi_get_handle(NULL, acpi_name, &hlsb);
> 
> assume those two main function is from ashok.
> 
> but assume that could make user omit \_SB_?

I looked at the ACPICA code and found that:
 - If a full path is specified in acpi_name, it ignores the arg hsb
("\_SB").
 - If a relative path is specified in acpi_name, it appends the arg hsb.

So, the code looks good to me; assuming that is the intent.

However, the error message below will show up like "\_SB.\_SB.PCIB" when
a full path is specified.

> >
> >> +     if (ACPI_FAILURE(status) || ACPI_FAILURE(status1)) {
> >> +             pr_err(PREFIX
> >> +     "acpi getting handle to <\\_SB.%s> failed inside notify_client\n",
> >> +                     acpi_name);
> >> +             return;
> >> +     }
> >> +
> >> +     status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
> >> +     if (ACPI_FAILURE(status)) {
> >> +             pr_err(PREFIX "Acquiring acpi namespace mutext failed\n");
> >> +             return;
> >> +     }
> >> +
> >> +     node = acpi_ns_validate_handle(hlsb);
> >> +     if (!node) {
> >> +             acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
> >> +             pr_err(PREFIX "Mapping handle to node failed\n");
> >> +             return;
> >> +     }
> >> +
> >> +     /*
> >> +      * Check for internal object and make sure there is a handler
> >> +      * registered for this object
> >> +      */
> >> +     obj_desc = acpi_ns_get_attached_object(node);
> >> +     if (obj_desc) {
> >> +             if (obj_desc->common_notify.notify_list[0]) {
> >
> > Is the above check necessary?  acpi_ev_queue_notify_request() sets up to
> > call the global handler, acpi_gbl_global_notify[0], even if the object
> > does not have a local handler registered.
> 
> Not sure.
> 
> maybe Len or other acpi guyes could answer your questions.

I think this check should be removed, but would like someone to
verify...

Thanks,
-Toshi


> Thanks
> 
> Yinghai Lu
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Yinghai Lu Sept. 4, 2012, 9:46 p.m. UTC | #4

On Tue, Sep 4, 2012 at 2:34 PM, Toshi Kani <[e-mail]> wrote:
> On Tue, 2012-09-04 at 12:17 -0700, Yinghai Lu wrote:
>  - If a full path is specified in acpi_name, it ignores the arg hsb
> ("\_SB").
>  - If a relative path is specified in acpi_name, it appends the arg hsb.
>
> So, the code looks good to me; assuming that is the intent.
>
> However, the error message below will show up like "\_SB.\_SB.PCIB" when
> a full path is specified.

I always use
echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify

and it works.

so assume that function can accept \_SB.PCIB and PCIB both.

Thanks

Yinghai
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Toshi Kani Sept. 4, 2012, 9:54 p.m. UTC | #5

On Tue, 2012-09-04 at 14:46 -0700, Yinghai Lu wrote:
> On Tue, Sep 4, 2012 at 2:34 PM, Toshi Kani <[e-mail]> wrote:
> > On Tue, 2012-09-04 at 12:17 -0700, Yinghai Lu wrote:
> >  - If a full path is specified in acpi_name, it ignores the arg hsb
> > ("\_SB").
> >  - If a relative path is specified in acpi_name, it appends the arg hsb.
> >
> > So, the code looks good to me; assuming that is the intent.
> >
> > However, the error message below will show up like "\_SB.\_SB.PCIB" when
> > a full path is specified.
> 
> I always use
> echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify
> 
> and it works.
> 
> so assume that function can accept \_SB.PCIB and PCIB both.

I agree.  And that's what I tried to say.


The error message below will be confusing when a (invalid) full path
name is specified, though.

>> +     if (ACPI_FAILURE(status) || ACPI_FAILURE(status1)) {
>> +             pr_err(PREFIX
>> +     "acpi getting handle to <\\_SB.%s> failed inside notify_client
\n",
>> +                     acpi_name);
>> +             return;
>> +     }


Thanks,
-Toshi

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Patch

===================================================================
---
 drivers/acpi/Kconfig   |   10 +++
 drivers/acpi/Makefile  |    1 
 drivers/acpi/sci_emu.c |  145 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 156 insertions(+)

Index: linux-2.6/drivers/acpi/Kconfig
===================================================================
--- linux-2.6.orig/drivers/acpi/Kconfig
+++ linux-2.6/drivers/acpi/Kconfig
@@ -272,6 +272,16 @@  config ACPI_BLACKLIST_YEAR
 	  Enter 0 to disable this mechanism and allow ACPI to
 	  run by default no matter what the year.  (default)
 
+config ACPI_SCI_EMULATE
+        bool "ACPI SCI Event Emulation Support"
+        depends on DEBUG_FS
+	default n
+	help
+	  This will enable your system to emulate sci hotplug event
+	  notification through proc file system. For example user needs to
+	  echo "XXX 0" > /sys/kernel/debug/acpi/sci_notify (where, XXX is
+	  a target ACPI device object name present under \_SB scope).
+
 config ACPI_DEBUG
 	bool "Debug Statements"
 	default n
Index: linux-2.6/drivers/acpi/sci_emu.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/acpi/sci_emu.c
@@ -0,0 +1,145 @@ 
+/*
+ *  Code to emulate SCI interrupt for Hotplug node insertion/removal
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <acpi/acpi_drivers.h>
+
+#include "internal.h"
+
+#include "acpica/accommon.h"
+#include "acpica/acnamesp.h"
+#include "acpica/acevents.h"
+
+#define _COMPONENT		ACPI_SYSTEM_COMPONENT
+ACPI_MODULE_NAME("sci_emu");
+MODULE_LICENSE("GPL");
+
+static struct dentry *sci_notify_dentry;
+
+static void sci_notify_client(char *acpi_name, u32 event)
+{
+	struct acpi_namespace_node *node;
+	acpi_status status, status1;
+	acpi_handle hlsb, hsb;
+	union acpi_operand_object *obj_desc;
+
+	status = acpi_get_handle(NULL, "\\_SB", &hsb);
+	status1 = acpi_get_handle(hsb, acpi_name, &hlsb);
+	if (ACPI_FAILURE(status) || ACPI_FAILURE(status1)) {
+		pr_err(PREFIX
+	"acpi getting handle to <\\_SB.%s> failed inside notify_client\n",
+			acpi_name);
+		return;
+	}
+
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		pr_err(PREFIX "Acquiring acpi namespace mutext failed\n");
+		return;
+	}
+
+	node = acpi_ns_validate_handle(hlsb);
+	if (!node) {
+		acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+		pr_err(PREFIX "Mapping handle to node failed\n");
+		return;
+	}
+
+	/*
+	 * Check for internal object and make sure there is a handler
+	 * registered for this object
+	 */
+	obj_desc = acpi_ns_get_attached_object(node);
+	if (obj_desc) {
+		if (obj_desc->common_notify.notify_list[0]) {
+			/*
+			 * Release the lock and queue the item for later
+			 * exectuion
+			 */
+			acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+			status = acpi_ev_queue_notify_request(node, event);
+			if (ACPI_FAILURE(status))
+				pr_err(PREFIX "acpi_ev_queue_notify_request failed\n");
+			else
+				pr_info(PREFIX "Notify event is queued\n");
+			return;
+		}
+	} else {
+		pr_info(PREFIX "Notify handler not registered for this device\n");
+	}
+
+	acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+	return;
+}
+
+static ssize_t sci_notify_write(struct file *file, const char __user *user_buf,
+				 size_t count, loff_t *ppos)
+{
+	u32 event;
+	char *name1 = NULL;
+	char *name2 = NULL;
+	const char *delim = " ";
+	char *temp_buf = NULL;
+	char *temp_buf_addr = NULL;
+
+	temp_buf = kmalloc(count+1, GFP_ATOMIC);
+	if (!temp_buf) {
+		pr_warn(PREFIX "sci_notify_wire: Memory allocation failed\n");
+		return count;
+	}
+	temp_buf[count] = '\0';
+	temp_buf_addr = temp_buf;
+	if (copy_from_user(temp_buf, user_buf, count))
+		goto out;
+
+	name1 = strsep(&temp_buf, delim);
+	name2 = strsep(&temp_buf, delim);
+
+	if (name1 && name2) {
+		ssize_t ret;
+		unsigned long val;
+
+		ret = kstrtoul(name2, 10, &val);
+		if (ret) {
+			pr_warn(PREFIX "unknown event\n");
+			goto out;
+		}
+
+		event = (u32)val;
+	} else {
+		pr_warn(PREFIX "unknown device\n");
+		goto out;
+	}
+
+	pr_info(PREFIX "ACPI device name is <%s>, event code is <%d>\n",
+		name1, event);
+
+	sci_notify_client(name1, event);
+
+out:
+	kfree(temp_buf_addr);
+	return count;
+}
+
+static const struct file_operations sci_notify_fops = {
+	.write = sci_notify_write,
+};
+
+static int __init acpi_sci_notify_init(void)
+{
+	if (acpi_debugfs_dir == NULL)
+		return -ENOENT;
+
+	sci_notify_dentry = debugfs_create_file("sci_notify", S_IWUSR,
+				acpi_debugfs_dir, NULL, &sci_notify_fops);
+	if (sci_notify_dentry == NULL)
+		return -ENODEV;
+
+	return 0;
+}
+
+device_initcall(acpi_sci_notify_init);
Index: linux-2.6/drivers/acpi/Makefile
===================================================================
--- linux-2.6.orig/drivers/acpi/Makefile
+++ linux-2.6/drivers/acpi/Makefile
@@ -31,6 +31,7 @@  acpi-$(CONFIG_ACPI_SLEEP)	+= proc.o
 # ACPI Bus and Device Drivers
 #
 acpi-y				+= bus.o glue.o
+acpi-$(CONFIG_ACPI_SCI_EMULATE)	+= sci_emu.o
 acpi-y				+= scan.o
 acpi-y				+= processor_core.o
 acpi-y				+= ec.o