Method and apparatus for suspending and resuming a keyboard controller

• US 5,446,906 A
• Filed: 06/30/1993
• Issued: 08/29/1995
• Est. Priority Date: 06/30/1993
• Status: Expired due to Term

• Current Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Original Assignee: Intel Corporation
• Inventors: Bland, Patrick M., Joshi, Jayesh M., Kardach, James P., Clarke, Grant L. Jr.
• Primary Examiner(s): Kim, Ken S.
• Application Number:
  US08/085,647
• Time in Patent Office: 790 Days
• Field of Search: 395/275, 395/575, 395/700, 395/750
• US Class Current: 713/323
• CPC Class Codes: G06F 21/83 input devices, e.g. keyboards, mice or controllers thereof

Abstract

A method and mechanism for suspending and resuming a keyboard controller. The present invention includes a method and mechanism for saving the state of an input device, such as a keyboard and/or mouse, such that the power to those devices may be removed. The keyboard controller of the present invention is capable of performing a password security function. The present invention allows the keyboard controller to be suspended and resumed without jeopardizing the password security function.

Claims

1. In a computer system having a processor and at least one memory, an improvement for conserving power comprising:

an input device coupled to the processor to input data and command selections to the processor;

a controller coupled the input device to prevent command selections from being received by the processor from the input device until at least one predetermined input is received from the input device when the computer system is in a security mode;

wherein, when in the security mode, the controller is responsive to the processor only for commands to save and restore state information of the input device, wherein the controller saves the state information of the input device in said at least one memory to allow power to the input device to be removed when the computer system enters a reduced power consumption state and restores the state information of the input device from said at least one memory after power to the input device has been restored when exiting the reduced power consumption state to ensure that the computer system returns to the security mode upon exiting the reduced power consumption state.

2. The computer system as defined in claim 1 wherein the input device comprises a keyboard.

3. The computer system as defined in claim 1 wherein the input device comprises a cursor control device.

4. The computer system as defined in claim 3 wherein the cursor control device comprises a mouse.

5. The computer system as defined in claim 1 wherein the controller saves state information of the input device in response to a first command from the processor.

6. The computer system as defined in claim 5 wherein the controller isolates at least one interface signal between the input device and the controller in response to the first command after saving state information of the input device.

7. The computer system as defined in claim 1 wherein the controller saves state information of the input device in response to a second command from the processor.

8. The computer system as defined in claim 7 wherein the controller activates at least one interface signal between the controller and the input device in response to the second command prior to restoring state information of the input device.

9. The computer system as defined in claim 1 wherein the controller comprises an on-chip memory for storing state information prior to the computer system entering the reduced power consumption state.

10. A computer system comprising:

a processor for executing a plurality of instructions;

a keyboard for inputting command selections to the processor, wherein the keyboard includes a keyboard state;

a keyboard controller coupled the keyboard and the processor for receiving the command selections from the keyboard and sending the command selections to the processor, wherein the keyboard controller prevents the command selections from being received by the processor until at least one predetermined input is received from the keyboard when in a security mode;

suspend mode generation means coupled to said processor for generating a suspend signal upon activation of a power suspend mode;

resume mode generation means coupled to said processor for generating a resume signal upon deactivation of the power suspend mode;

wherein, when in the security mode, the keyboard controller is responsive to the processor only for commands to save and restore state information of the input device, wherein the keyboard controller saves the state information of the keyboard to allow power to the keyboard to be removed when the computer system enters the power suspend mode and restores the state information to the keyboard after power to the keyboard has been restored when exiting the power suspend mode to ensure that the computer system returns to the security mode upon exiting the power suspend mode.

11. The computer system as defined in claim 10 wherein the keyboard controller isolates at least one interface signal between the keyboard and the keyboard controller in response to the first command after saving the state information of the keyboard.

12. The computer system as defined in claim 11 wherein the keyboard controller activates said at least one interface signal between the keyboard controller and the keyboard in response to the second command prior to restoring the state information to the keyboard.

13. A computer system comprising:

a processor for executing a plurality of instructions;

a keyboard for inputting command selections to the processor, wherein the keyboard includes a keyboard state;

a cursor control device for controlling cursor movement, wherein the cursor control device includes a cursor control state;

a keyboard controller coupled to the keyboard, the cursor control device and the processor for receiving the command selections and cursor control movement and sending the command selections and cursor control movement to the processor, wherein the keyboard controller includes means for preventing the command selections and cursor control movement from being received by the processor until at least one predetermined input is received from the keyboard when in a password security mode;

suspend mode generation means coupled to said processor for generating a suspend signal upon activation of a power suspend mode;

resume mode generation means coupled to said processor for generating a resume signal upon deactivation of the power suspend mode;

wherein the processor issues a first command to the keyboard controller in response to the suspend signal and a second command to the keyboard controller in response to the resume signal;

wherein, when in the password security mode, the keyboard controller receives the first command and the second command, and further wherein the keyboard controller saves the keyboard state information and the cursor control device state information in a memory in response to the first command and restores the keyboard state information and the cursor control device state information from the memory in response to the second command to ensure that the computer system returns to the password security mode when the computer system was in the password security mode upon entering the power suspend mode.

14. The computer system as defined in claim 13 wherein the keyboard controller isolates interface signals between the keyboard and the keyboard controller and between the cursor control device and the keyboard controller in response to the first command after saving the state information of the keyboard and the cursor control device respectively.

15. The computer system as defined in claim 14 wherein the keyboard controller activates said interface signal between the keyboard controller and the keyboard and between the keyboard controller and the cursor control device in response to the second command prior to restoring state information of the keyboard and the cursor control device respectively.