Re: [PATCH] ACPI: Enable SCI_EMULATE to manually simulate physicalhotplug testing.

[Yinghai Lu]

On Tue, Sep 4, 2012 at 9:27 AM, Toshi Kani <toshi.kani@xxxxxx> wrote:
> On Mon, 2012-09-03 at 14:27 -0700, Yinghai Lu wrote:
>> From: Ashok Raj <ashok.raj@xxxxxxxxx>
>>
>> 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 <yinghai@xxxxxxxxxx>
>> Cc: Len Brown <lenb@xxxxxxxxxx>
>> Cc: linux-acpi@xxxxxxxxxxxxxxx
>>
>> ===================================================================
>> ---
>>  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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