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Diffstat (limited to 'Documentation/ABI/testing/dell-smbios-wmi')
| -rw-r--r-- | Documentation/ABI/testing/dell-smbios-wmi | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/dell-smbios-wmi b/Documentation/ABI/testing/dell-smbios-wmi new file mode 100644 index 000000000000..fc919ce16008 --- /dev/null +++ b/Documentation/ABI/testing/dell-smbios-wmi @@ -0,0 +1,41 @@ +What: /dev/wmi/dell-smbios +Date: November 2017 +KernelVersion: 4.15 +Contact: "Mario Limonciello" <mario.limonciello@dell.com> +Description: + Perform SMBIOS calls on supported Dell machines. + through the Dell ACPI-WMI interface. + + IOCTL's and buffer formats are defined in: + <uapi/linux/wmi.h> + + 1) To perform an SMBIOS call from userspace, you'll need to + first determine the minimum size of the calling interface + buffer for your machine. + Platforms that contain larger buffers can return larger + objects from the system firmware. + Commonly this size is either 4k or 32k. + + To determine the size of the buffer read() a u64 dword from + the WMI character device /dev/wmi/dell-smbios. + + 2) After you've determined the minimum size of the calling + interface buffer, you can allocate a structure that represents + the structure documented above. + + 3) In the 'length' object store the size of the buffer you + determined above and allocated. + + 4) In this buffer object, prepare as necessary for the SMBIOS + call you're interested in. Typically SMBIOS buffers have + "class", "select", and "input" defined to values that coincide + with the data you are interested in. + Documenting class/select/input values is outside of the scope + of this documentation. Check with the libsmbios project for + further documentation on these values. + + 6) Run the call by using ioctl() as described in the header. + + 7) The output will be returned in the buffer object. + + 8) Be sure to free up your allocated object. |