Smbios; Usb Legacy Support - HP dx7300 Technical Reference Manual

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
0 BIOS Information
1 System Information
2 Base board information
3 System Enclosure or Chassis
4 Processor Information
7 Cache Information
8 Port Connector Information
9 System Slots
13 BIOS Language Information
15 System Event Log Information
16 Physical Memory Array
17 Memory Devices
19 Memory Array Mapped Addresses
20 Memory Device Mapped Addresses
31 Boot Integrity Service Entry Point
32 System 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
BIOS ROM
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