Intel® 400 Series Chipset On-Package Platform Controller Hub
Online Register Database
ID | Date | Version | Classification |
---|---|---|---|
615146 | 08/09/2019 | 1.2 | Public |
Port N Hardware LPM Control Register (PORTHLPMCN) – Offset 48c
Note that this Port Hardware Control register is available at the following offsets for all applicable USB ports:
USB2 Port 1: 48Ch
USB2 Port 2: 49Ch
USB2 Port 3: 4ACh
.....
USB2 Port 9: 50Ch
USB2 Port 10: 51Ch
This register is reset only by platform hardware during cold reset or in response to a Host Controller Reset (HCRST).The definition for the fields depend on the protocol supported.
For USB3 this register is reserved and shall be treated by software as RsvdP.
For USB2 the definition is given below. Fields contain parameters neccessary for xHC to automatically generate an LPM Token to the downstream device.
Bit Range | Default | Access | Field Name and Description |
---|---|---|---|
30:14 | - | - | Reserved
|
13:10 | 0h | RW | Host Initiated Resume Duration-Deep (HIRDD) System software sets this field to indicate to the recipient device how long the xHC will drive resume if an exit from L1. The HIRDD value is is encoded as follows: |
9:2 | 00h | RW/P | L1 Timeout (L1_TO) Timeout value for L1 inactivity timer. This field shall be set to 00h by assertion of PR to '1'. Following are permissible values: |
1:0 | 0h | RW/P | Host Initiated Resume Duration Mode (HIRDM) Indicates which HIRD value should be used. Following are permissible values: |