BIOS ROM

8.6 SMBIOS

In support of the DMI specification the PnP functions 50h and 51h are used to retrieve the SMBIOS data. Function 50h retrieves the number of structures, size of the largest structure, and SMBIOS version. Function 51h retrieves a specific structure. This system supports SMBIOS version 2.4 and the following structure types:

Type Data

0BIOS Information

1System Information

2Base board information

3System Enclosure or Chassis

4Processor Information

7Cache Information

8Port Connector Information

9System Slots

13

BIOS Language Information

15System Event Log Information

16Physical Memory Array

17Memory Devices

19Memory Array Mapped Addresses

20Memory Device Mapped Addresses

31Boot Integrity Service Entry Point

32System Boot Information

✎System information on these systems is handled exclusively through the SMBIOS.

8.7 USB Legacy Support

The BIOS ROM checks the USB port, during POST, for the presence of a USB keyboard. This allows a system with only a USB keyboard to be used during ROM-based setup and also on a system with an OS that does not include a USB driver.

On such a system a keystroke will generate an SMI and the SMI handler will retrieve the data from the device and convert it to PS/2 data. The data will be passed to the keyboard controller and processed as in the PS/2 interface. Changing the delay and/or typematic rate of a USB keyboard though BIOS function INT 16 is not supported.

 

Technical Reference Guide

www.hp.com

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