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.rohar@xxxxxxxxx> --- 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 <mjg@xxxxxxxxxx> + * Copyright (C) 2014-2015 Pali Rohár <pali.rohar@xxxxxxxxx> * * Portions based on wistron_btns.c: * Copyright (C) 2005 Miloslav Trmac <mitr@xxxxxxxx> @@ -38,14 +39,18 @@ #include <acpi/video.h> MODULE_AUTHOR("Matthew Garrett <mjg@xxxxxxxxxx>"); +MODULE_AUTHOR("Pali Rohár <pali.rohar@xxxxxxxxx>"); 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 -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
