According to Dell WMI document mentioned in ML dicussion archived at
http://www.spinics.net/lists/platform-driver-x86/msg07220.html OS should
check Dell WMI descriptor structure. Structure also provide Dell WMI
interface version which is used later.
Signed-off-by: Pali Rohár <pali.ro...@gmail.com>
---
drivers/platform/x86/dell-wmi.c | 78 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 76 insertions(+), 2 deletions(-)
diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 57402c4..09ee8ed 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -2,6 +2,7 @@
* Dell WMI hotkeys
*
* Copyright (C) 2008 Red Hat <m...@redhat.com>
+ * Copyright (C) 2014-2015 Pali Rohár <pali.ro...@gmail.com>
*
* Portions based on wistron_btns.c:
* Copyright (C) 2005 Miloslav Trmac <m...@volny.cz>
@@ -38,14 +39,18 @@
#include <acpi/video.h>
MODULE_AUTHOR("Matthew Garrett <m...@redhat.com>");
+MODULE_AUTHOR("Pali Rohár <pali.ro...@gmail.com>");
MODULE_DESCRIPTION("Dell laptop WMI hotkeys driver");
MODULE_LICENSE("GPL");
#define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"
+#define DELL_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
static int acpi_video;
+static u32 dell_wmi_interface_version;
MODULE_ALIAS("wmi:"DELL_EVENT_GUID);
+MODULE_ALIAS("wmi:"DELL_DESCRIPTOR_GUID);
/*
* Certain keys are flagged as KE_IGNORE. All of these are either
@@ -422,16 +427,85 @@ static void __init find_hk_type(const struct dmi_header
*dm, void *dummy)
}
}
+/**
+ * Descriptor buffer is 128 byte long and contains:
+ *
+ * Name Offset Length Value
+ * Vendor Signature 0 4 "DELL"
+ * Object Signature 4 4 " WMI"
+ * WMI Interface Version 8 4 <version>
+ * WMI buffer length 12 4 4096
+ */
+static int __init dell_wmi_check_descriptor_buffer(void)
+{
+ struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ acpi_status status;
+ u32 *buffer;
+
+ status = wmi_query_block(DELL_DESCRIPTOR_GUID, 0, &out);
+ if (ACPI_FAILURE(status)) {
+ pr_err("Cannot read Dell descriptor buffer - %d\n", status);
+ return status;
+ }
+
+ obj = (union acpi_object *)out.pointer;
+ if (!obj) {
+ pr_err("Dell descriptor buffer is empty\n");
+ return -EINVAL;
+ }
+
+ if (obj->type != ACPI_TYPE_BUFFER) {
+ pr_err("Cannot read Dell descriptor buffer\n");
+ kfree(obj);
+ return -EINVAL;
+ }
+
+ if (obj->buffer.length != 128) {
+ pr_err("Dell descriptor buffer has invalid length (%d)\n",
+ obj->buffer.length);
+ kfree(obj);
+ return -EINVAL;
+ }
+
+ buffer = (u32 *)obj->buffer.pointer;
+
+ if (buffer[0] != 0x4C4C4544 && buffer[1] != 0x494D5720)
+ pr_warn("Dell descriptor buffer has invalid signature (%*ph)\n",
+ 8, buffer);
+
+ if (buffer[2] != 0 && buffer[2] != 1)
+ pr_warn("Dell descriptor buffer has unknown version (%d)\n",
+ buffer[2]);
+
+ if (buffer[3] != 4096)
+ pr_warn("Dell descriptor buffer has invalid buffer length
(%d)\n",
+ buffer[3]);
+
+ dell_wmi_interface_version = buffer[2];
+
+ pr_info("Detected Dell WMI interface version %u\n",
+ dell_wmi_interface_version);
+
+ kfree(obj);
+ return 0;
+}
+
static int __init dell_wmi_init(void)
{
int err;
acpi_status status;
- if (!wmi_has_guid(DELL_EVENT_GUID)) {
- pr_warn("No known WMI GUID found\n");
+ if (!wmi_has_guid(DELL_EVENT_GUID) ||
+ !wmi_has_guid(DELL_DESCRIPTOR_GUID)) {
+ pr_warn("Dell WMI GUID were not found\n");
return -ENODEV;
}
+ err = dell_wmi_check_descriptor_buffer();
+ if (err)
+ return err;
+
dmi_walk(find_hk_type, NULL);
acpi_video = acpi_video_get_backlight_type() != acpi_backlight_vendor;
--
1.7.9.5
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