Acer violate the ACPI-WMI spec by declaring some of their data blocks as
expensive, but with no corresponding WCxx method. There is already some
workaround code in to handle the initial WCxx call (we just ignore a
failure here); but we need to properly check if the second, "clean up",
WCxx call is actually needed or not, rather than fail simply because it
isn't there.
Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: Len Brown <len.brown@intel.com>
Even if we don't want to register the WMI driver, we should initialize
the wmi_blocks list to be empty, since we don't want the wmi helper
functions to oops just because that basic list has not even been set up.
With this, "find_guid()" will happily return "not found" rather than
oopsing all over the place, and the callers will then just automatically
return false or AE_NOT_FOUND as appropriate.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following is an implementation of the Windows Management
Instrumentation (WMI) ACPI interface mapper (PNP0C14).
What it does:
Parses the _WDG method and exports functions to process WMI method calls,
data block query/ set commands (both based on GUID) and does basic event
handling.
How: WMI presents an in kernel interface here (essentially, a minimal
wrapper around ACPI)
(const char *guid assume the 36 character ASCII representation of
a GUID - e.g. 67C3371D-95A3-4C37-BB61-DD47B491DAAB)
wmi_evaluate_method(const char *guid, u8 instance, u32 method_id,
const struct acpi_buffer *in, struct acpi_buffer *out)
wmi_query_block(const char *guid, u8 instance,
struct acpi_buffer *out)
wmi_set_block(const char *guid, u38 instance,
const struct acpi_buffer *in)
wmi_install_notify_handler(acpi_notify_handler handler);
wmi_remove_notify_handler(void);
wmi_get_event_data(u32 event, struct acpi_buffer *out)
wmi_has_guid(const char guid*)
wmi_has_guid() is a helper function to find if a GUID exists or not on the
system (a quick and easy way for WMI dependant drivers to see if the
the method/ block they want exists, since GUIDs are supposed to be unique).
Event handling - allow a WMI based driver to register a notifier handler
for each GUID with WMI. When a notification is sent to a GUID in WMI, the
handler registered with WMI is then called (it is left to the caller to
ask for the WMI event data associated with the GUID, if needed).
What it won't do:
Unicode - The MS article[1] calls for converting between ASCII and Unicode (or
vice versa) if a GUID is marked as "string". This is left up to the calling
driver.
Handle a MOF[1] - the WMI mapper just exports methods, data and events to
userspace. MOF handling is down to userspace.
Userspace interface - this will be added later.
[1] http://www.microsoft.com/whdc/system/pnppwr/wmi/wmi-acpi.mspx
===
ChangeLog
==
v1 (2007-10-02):
* Initial release
v2 (2007-10-05):
* Cleaned up code - split up super "wmi_evaluate_block" -> each external
symbol now handles its own ACPI calls, rather than handing off to
a "super" method (and in turn, is a lot simpler to read)
* Added a find_guid() symbol - return true if a given GUID exists on
the system
* wmi_* functions now return type acpi_status (since they are just
fancy wrappers around acpi_evaluate_object())
* Removed extra debug code
v3 (2007-10-27)
* More code clean up - now passes checkpatch.pl
* Change data block calls - ref MS spec, method ID is not required for
them, so drop it from the function parameters.
* Const'ify guid in the function call parameters.
* Fix _WDG buffer handling - copy the data to our own private structure.
* Change WMI from tristate to bool - otherwise the external functions are
not exported in linux/acpi.h if you try to build WMI as a module.
* Fix more flag comparisons.
* Add a maintainers entry - since I wrote this, I should take the blame
for it.
v4 (2007-10-30)
* Add missing brace from after fixing checkpatch errors.
* Rewrote event handling - allow external drivers to register with WMI to
handle WMI events
* Clean up flags and sanitise flag handling
v5 (2007-11-03)
* Add sysfs interface for userspace. Export events over netlink again.
* Remove module left overs, fully convert to built-in driver.
* Tweak in-kernel API to use u8 for instance, since this is what the GUID
blocks use (so instance cannot be greater than u8).
* Export wmi_get_event_data() for in kernel WMI drivers.
v6 (2007-11-07)
* Split out userspace into a different patch
v7 (2007-11-20)
* Fix driver to handle multiple PNP0C14 devices - store all GUIDs using
the kernel's built in list functions, and just keep adding to the list
every time we handle a PNP0C14 devices - GUIDs will always be unique,
and WMI callers do not know or care about different devices.
* Change WMI event handler registration to use its' own event handling
struct; we should not pass an acpi_handle down to any WMI based drivers
- they should be able to function with only the calls provided in WMI.
* Update my e-mail address
v8 (2007-11-28)
* Convert back to a module.
* Update Kconfig to default to building as a module.
* Remove an erroneous printk.
* Simply comments for string flag (since we now leave the handling to the
caller).
v9 (2007-12-07)
* Add back missing MODULE_DEVICE_TABLE for autoloading
* Checkpatch fixes
v10 (2007-12-12)
* Workaround broken GUIDs declared expensive without a WCxx method.
* Minor cleanups
v11 (2007-12-17)
* More fixing for broken GUIDs declared expensive without a WCxx method.
* Add basic EmbeddedControl region handling.
v12 (2007-12-18)
* Changed EC region handling code, as per Alexey's comments.
v13 (2007-12-27)
* Changed event handling so that we can have one event handler registered
per GUID, as per Matthew Garrett's suggestion.
v14 (2008-01-12)
* Remove ACPI debug statements
v15 (2008-02-01)
* Replace two remaining 'x == NULL' type tests with '!x'
v16 (2008-02-05)
* Change MAINTAINERS entry, as I am not, and never have been, paid to work
on WMI
* Remove 'default' line from Kconfig
Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
CC: Matthew Garrett <mjg59@srcf.ucam.org>
CC: Alexey Starikovskiy <aystarik@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
