Propose WMI patch

Hi,

I wanted to propose a ACPI-WMI API change. Instead of having, wmi_has_guid returning a boolean, why not returning a acpi_status. It would allow extented error handling, and it would look more ACPI style :)

index cfe2c83..cdff9bf 100644
@@ -194,14 +194,16 @@ static bool wmi_parse_guid(const u8 *src, u8 *dest)
 	return true;
 }
 
-static bool find_guid(const char *guid_string, struct wmi_block **out)
+static acpi_status find_guid(const char *guid_string, struct wmi_block **out)
 {
 	char tmp[16], guid_input[16];
 	struct wmi_block *wblock;
 	struct guid_block *block;
 	struct list_head *p;
 
-	wmi_parse_guid(guid_string, tmp);
+	if (!wmi_parse_guid(guid_string, tmp))
+		return AE_BAD_PARAMETER;
+
 	wmi_swap_bytes(tmp, guid_input);
 
 	list_for_each(p, &wmi_blocks.list) {

@@ -211,10 +213,10 @@ static bool find_guid(const char *guid_string, struct 

wmi_block **out)
if (memcmp(block->guid, guid_input, 16) == 0) {
if (out)
*out = wblock;
- return 1;
+ return AE_OK;
}
}
- return 0;
+ return AE_NOT_FOUND;
}

/*
@@ -241,8 +243,10 @@ u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
union acpi_object params[3];
char method[4] = "WM";

- if (!find_guid(guid_string, &wblock))
- return AE_BAD_ADDRESS;
+ status = find_guid(guid_string, &wblock);
+
+ if (ACPI_FAILURE(status))
+ return status;

block = &wblock->gblock;
handle = wblock->handle;
@@ -303,7 +307,9 @@ struct acpi_buffer *out)
if (!guid_string || !out)
return AE_BAD_PARAMETER;

- if (!find_guid(guid_string, &wblock))
+ status = find_guid(guid_string, &wblock);
+
+ if (ACPI_FAILURE(status))
return AE_BAD_ADDRESS;

block = &wblock->gblock;
@@ -377,6 +383,7 @@ const struct acpi_buffer *in)
struct guid_block *block = NULL;
struct wmi_block *wblock = NULL;
acpi_handle handle;
+ acpi_status status;
struct acpi_object_list input;
union acpi_object params[2];
char method[4] = "WS";
@@ -384,7 +391,9 @@ const struct acpi_buffer *in)
if (!guid_string || !in)
return AE_BAD_DATA;

- if (!find_guid(guid_string, &wblock))
+ status = find_guid(guid_string, &wblock);
+
+ if (ACPI_FAILURE(status))
return AE_BAD_ADDRESS;

block = &wblock->gblock;
@@ -427,12 +436,14 @@ acpi_status wmi_install_notify_handler(const char *guid,
wmi_notify_handler handler, void *data)
{
struct wmi_block *block;
+ acpi_status status;

if (!guid || !handler)
return AE_BAD_PARAMETER;

- find_guid(guid, &block);
- if (!block)
+ status = find_guid(guid, &block);
+
+ if (ACPI_FAILURE(status))
return AE_NOT_EXIST;

if (block->handler)
@@ -453,12 +464,14 @@ EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
acpi_status wmi_remove_notify_handler(const char *guid) {
struct wmi_block *block;
+ acpi_status status;

if (!guid)
return AE_BAD_PARAMETER;

- find_guid(guid, &block);
- if (!block)
+ status = find_guid(guid, &block);
+
+ if (ACPI_FAILURE(status))
return AE_NOT_EXIST;

if (!block->handler)
@@ -507,15 +520,21 @@ acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
EXPORT_SYMBOL_GPL(wmi_get_event_data);

/**
- * wmi_has_guid - Check if a GUID is available
+ * wmi_is_guid_present - Check if a GUID is available
* @guid_string: 36 char string of the form
fa50ff2b-f2e8-45de-83fa-65417f2f49ba
*
* Check if a given GUID is defined by _WDG
*/
-bool wmi_has_guid(const char *guid_string) +acpi_status wmi_is_guid_present(const char *guid_string)
{
return find_guid(guid_string, NULL);
}
+EXPORT_SYMBOL_GPL(wmi_is_guid_present);
+
+bool wmi_has_guid(const char *guid_string)
+{
+ return ACPI_SUCCESS(find_guid(guid_string, NULL));
+}
EXPORT_SYMBOL_GPL(wmi_has_guid);

/*

index 702f79d..26f9c0a 100644
@@ -198,6 +198,7 @@ extern acpi_status wmi_install_notify_handler(const char 

*guid,
wmi_notify_handler handler, void *data);
extern acpi_status wmi_remove_notify_handler(const char *guid); extern acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out);
+extern acpi_status wmi_is_guid_present(const char *guid);
extern bool wmi_has_guid(const char *guid);

#endif /* CONFIG_ACPI_WMI */

NAK.

We're not interested in ACPI error codes here, since we're never going to do anything with them.

We only care if the DSDT exists or not with this method - it's just a means of detection for other drivers.

-Carlos

E-Mail: [email protected]
Web: strangeworlds.co.uk
GPG Key ID: 0x23EE722D

s/DSDT/GUID/

-Carlos

E-Mail: [email protected]
Web: strangeworlds.co.uk
GPG Key ID: 0x23EE722D

For instance, it would be nice to be able to do this,

for (i = 0; i < ARRAY_SIZE(laptop->methods); i++)
        laptop->methods[i].status =
wmi_is_guid_present(laptop->methods[i].guid);

instead of

for (i = 0; i < ARRAY_SIZE(laptop->methods); i++) if (wmi_has_guid(laptop->methods[i].guid)) laptop->methods[i].status = AE_OK; else
                laptop->methods[i].status = AE_NOT_FOUND;

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Why not just do:

for (i = 0; i < ARRAY_SIZE(laptop->methods); i++)

         laptop->methods[i].exists =
                 wmi_is_guid_present(laptop->methods[i].guid);

I don't see why you need an ACPI status here, when a simple bool will do just fine?

Otherwise, instead of being able to do this:

if (laptop->methods[i].exists) {
        /* do something */
}

you end up having to use one of the ACPI status wrappers all the time:

if (ACPI_SUCCESS(laptop->methods[i].status)) {
         /* do something */
}

-Carlos

E-Mail: [email protected]
Web: strangeworlds.co.uk
GPG Key ID: 0x23EE722D
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yes, a bool should suffice, thanks :)

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