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platform/x86: wmi: Always evaluate _WED when receiving an event

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The ACPI WMI specification states:

	"The _WED control method is evaluated by the mapper in
	 response to receiving a notification from a control
	 method."

This means that _WED should be evaluated unconditionally even
if no WMI event consumers are present.
Some firmware implementations actually depend on this behavior
by storing the event data inside a queue which will fill up if
the WMI core stops retrieving event data items due to no
consumers being present

Fix this by always evaluating _WED even if no WMI event consumers
are present.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20240219115919.16526-4-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
This commit is contained in:
Armin Wolf 2024-02-19 12:59:17 +01:00 committed by Ilpo Järvinen
parent 125619112d
commit 56230bd733
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GPG Key ID: 59AC4F6153E5CE31
1 changed files with 49 additions and 18 deletions
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67
drivers/platform/x86/wmi.c
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@ -1206,37 +1206,46 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
}
}
static void wmi_notify_driver(struct wmi_block *wblock)
static int wmi_get_notify_data(struct wmi_block *wblock, union acpi_object **obj)
{
struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj = NULL;
acpi_status status;
if (!driver->no_notify_data) {
status = get_event_data(wblock, &data);
if (ACPI_FAILURE(status)) {
dev_warn(&wblock->dev.dev, "Failed to get event data\n");
return;
}
if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags)) {
*obj = NULL;
return 0;
}
obj = data.pointer;
if (!obj) {
dev_warn(&wblock->dev.dev, "Event contains no event data\n");
return;
}
status = get_event_data(wblock, &data);
if (ACPI_FAILURE(status)) {
dev_warn(&wblock->dev.dev, "Failed to get event data\n");
return -EIO;
}
*obj = data.pointer;
return 0;
}
static void wmi_notify_driver(struct wmi_block *wblock, union acpi_object *obj)
{
struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
if (!obj && !driver->no_notify_data) {
dev_warn(&wblock->dev.dev, "Event contains no event data\n");
return;
}
if (driver->notify)
driver->notify(&wblock->dev, obj);
kfree(obj);
}
static int wmi_notify_device(struct device *dev, void *data)
{
struct wmi_block *wblock = dev_to_wblock(dev);
union acpi_object *obj;
u32 *event = data;
int ret;
if (!(wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *event))
return 0;
@ -1246,10 +1255,32 @@ static int wmi_notify_device(struct device *dev, void *data)
* Because of this the WMI driver notify handler takes precedence.
*/
if (wblock->dev.dev.driver && wblock->driver_ready) {
wmi_notify_driver(wblock);
ret = wmi_get_notify_data(wblock, &obj);
if (ret >= 0) {
wmi_notify_driver(wblock, obj);
kfree(obj);
}
} else {
if (wblock->handler)
if (wblock->handler) {
wblock->handler(*event, wblock->handler_data);
} else {
/* The ACPI WMI specification says that _WED should be
* evaluated every time an notification is received, even
* if no consumers are present.
*
* Some firmware implementations actually depend on this
* by using a queue for events which will fill up if the
* WMI driver core stops evaluating _WED due to missing
* WMI event consumers.
*
* Because of this we need this seemingly useless call to
* wmi_get_notify_data() which in turn evaluates _WED.
*/
ret = wmi_get_notify_data(wblock, &obj);
if (ret >= 0)
kfree(obj);
}
}
up_read(&wblock->notify_lock);