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: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index a65d974f387a4fd8fb5ae65b209292b5f83e557e..ed2004be13cfcc58a6c9598a234433d9c76ba078 100644 (file)
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -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.

diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index e38258a82be532e8820143c8b85908571d1744cb..65edd93df7de998018ff2a4ec8d9805c765b58d2 100644 (file)
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -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();
 }