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Commit e09c4d5b authored by Michał Kępień's avatar Michał Kępień Committed by Darren Hart
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dell-wmi: enable receiving WMI events on Dell Vostro V131 

On some laptop models (e.g. Dell Vostro V131), WMI events are not
generated until a specific SMBIOS request is issued to register an event
listener [1].  As there seems to be no ACPI method or SMBIOS request to
determine without possible side effects whether a given machine needs to
issue this SMBIOS request in order to receive WMI events, DMI matching
is used to whitelist the models which need it.

[1] https://lists.us.dell.com/pipermail/libsmbios-devel/2015-July/000612.html



Signed-off-by: default avatarMichał Kępień <kernel@kempniu.pl>
Reviewed-by: default avatarPali Rohár <pali.rohar@gmail.com>
Signed-off-by: default avatarDarren Hart <dvhart@linux.intel.com>
parent 0db2180f

drivers/platform/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -124,6 +124,7 @@ config DELL_WMI 
	depends on DMI

	depends on INPUT

	depends on ACPI_VIDEO || ACPI_VIDEO = n

	depends on DELL_SMBIOS

	select INPUT_SPARSEKMAP

	---help---

	  Say Y here if you want to support WMI-based hotkeys on Dell laptops.

drivers/platform/x86/dell-wmi.c

+66 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/string.h>

#include <linux/dmi.h>

#include <acpi/video.h>

#include "dell-smbios.h"



MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");

MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
@@ -47,10 +48,29 @@ MODULE_LICENSE("GPL"); 
#define DELL_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"



static u32 dell_wmi_interface_version;

static bool wmi_requires_smbios_request;



MODULE_ALIAS("wmi:"DELL_EVENT_GUID);

MODULE_ALIAS("wmi:"DELL_DESCRIPTOR_GUID);



static int __init dmi_matched(const struct dmi_system_id *dmi)

{

	wmi_requires_smbios_request = 1;

	return 1;

}



static const struct dmi_system_id dell_wmi_smbios_list[] __initconst = {

	{

		.callback = dmi_matched,

		.ident = "Dell Vostro V131",

		.matches = {

			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),

			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),

		},

	},

	{ }

};



/*

 * Certain keys are flagged as KE_IGNORE. All of these are either

 * notifications (rather than requests for change) or are also sent
@@ -597,6 +617,38 @@ static int __init dell_wmi_check_descriptor_buffer(void) 
	return 0;

}



/*

 * According to Dell SMBIOS documentation:

 *

 * 17  3  Application Program Registration

 *

 *     cbArg1 Application ID 1 = 0x00010000

 *     cbArg2 Application ID 2

 *            QUICKSET/DCP = 0x51534554 "QSET"

 *            ALS Driver   = 0x416c7353 "AlsS"

 *            Latitude ON  = 0x4c6f6e52 "LonR"

 *     cbArg3 Application version or revision number

 *     cbArg4 0 = Unregister application

 *            1 = Register application

 *     cbRes1 Standard return codes (0, -1, -2)

 */



static int dell_wmi_events_set_enabled(bool enable)

{

	struct calling_interface_buffer *buffer;

	int ret;



	buffer = dell_smbios_get_buffer();

	buffer->input[0] = 0x10000;

	buffer->input[1] = 0x51534554;

	buffer->input[3] = enable;

	dell_smbios_send_request(17, 3);

	ret = buffer->output[0];

	dell_smbios_release_buffer();



	return dell_smbios_error(ret);

}



static int __init dell_wmi_init(void)

{

	int err;
@@ -624,12 +676,26 @@ static int __init dell_wmi_init(void) 
		return -ENODEV;

	}



	dmi_check_system(dell_wmi_smbios_list);



	if (wmi_requires_smbios_request) {

		err = dell_wmi_events_set_enabled(true);

		if (err) {

			pr_err("Failed to enable WMI events\n");

			wmi_remove_notify_handler(DELL_EVENT_GUID);

			dell_wmi_input_destroy();

			return err;

		}

	}



	return 0;

}

module_init(dell_wmi_init);



static void __exit dell_wmi_exit(void)

{

	if (wmi_requires_smbios_request)

		dell_wmi_events_set_enabled(false);

	wmi_remove_notify_handler(DELL_EVENT_GUID);

	dell_wmi_input_destroy();

}