System and method for ambient light sensor testing

Abstract

An ambient light sensor testing module running on an information handling system verifies that an ambient light sensor managing brightness of an information handling system display is active and responding correctly. The testing module sets the display at first and second manually-selectable brightness levels and compares the brightness set from the first and second manually-selectable brightness levels when the ambient light sensor is engaged to set display brightness. An excessive difference between the brightness set by the ambient light sensor from the first and second manually-selectable brightness levels indicates a faulty ambient light sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference number throughout the several figures designates a like or similar element.

FIG. 1 depicts a block diagram of an information handling system having an ambient light sensor testing module; and

FIG. 2 depicts a flow diagram of a process for testing an ambient light sensor.

DETAILED DESCRIPTION

Ambient light sensor testing capability is integrated within a portable information handling system. For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components.

Referring now to FIG. 1, a block diagram depicts an information handling system 10 having an ambient light sensor testing module. Information handling system 10 is configured as a portable system having an integrated liquid crystal display (LCD) 12 to present visual information generated by processing components, such as a CPU 14, hard disk drive 16, RAM 18, network interface card 20 and chipset 22, which are disposed in a housing 24. An embedded controller 26 receives user inputs through input devices and a graphics processor unit (GPU) 28 formats visual information for presentation at display 12. An inverter 30 provides power to a backlight, CCFL 32, which illuminates the image presented at display 12. Inverter 30 provides variable settings of power to backlight 32 to provide variable brightness levels. Brightness settings are automatically varied based on ambient light detected proximate display 12 by an ambient light sensor (ALS) 34. For example, as ALS 34 detects increased levels of ambient light brightness, inverter 30 provides increased brightness settings for illuminating backlight 32. As ALS 34 detects decreased levels of ambient light brightness, inverter 30 provides decreased brightness settings for illuminating backlight 32. Brightness settings are, alternatively, manually selectable based on user inputs, such as the function up/down arrow combination input through embedded controller 26. For instance, eight step brightness values are manually-selectable from a minimum brightness setting to a maximum brightness setting.

In order to test the operation of ALS 34, firmware instructions are integrated into a processing component, such as a microcontroller operating in inverter 30, embedded controller 26 or a BIOS 36 running on chipset 22, which alters brightness settings at inverter 30 and checks that ALS 34 returns the brightness setting to substantially the same value. For instance, a testing module 38 is included in BIOS 36 to test the repeatability of the response of ALS 34. Testing module 38 automatically commands a brightness selector 40 to set the manually-selectable minimum value at inverter 30. Testing module 38 then automatically engages ALS 34 to adjust the brightness of display 12 to compensate for ambient lighting conditions. After a slight delay to stabilize the brightness setting made by ALS 34, a brightness setting detector 42 reads the brightness setting at inverter 30. After the reading is complete, testing module 38 next automatically commands brightness selector 40 to set the manually-selectable maximum value at inverter 30. Testing module 38 then once again automatically engages ALS 34 to adjust the brightness of display 12 to compensate for ambient lighting conditions. After a slight delay, brightness setting detector 42 reads the brightness setting at inverter 30 as set by ALS 34. Testing module 38 compares the two ALS brightness settings read by brightness setting detector 42 to determine an ALS failure if the difference is too great or to determine an ALS pass if the two ALS brightness settings are substantially similar. The pass or fail status may be communicated to a network location through NIC 20 or presented at display 12. Because ALS testing is internally supported, an ALS test may be automatically performed during manufacture and communicated to a diagnostics server to ensure proper ALS operation before shipment of the information handling system.

Referring now to FIG. 2, a flow diagram depicts a process for testing an ambient light sensor. The process starts at step 44 with initiation of an ALS test and continues to step 46 to set the test iteration value to zero. At step 48, the SMBus mode is enabled to support two-way communication between the inverter and the testing module. At step 50, a determination is made of whether the test iteration value is zero, and, if so, the process continues to step 52 to set the display panel brightness to maximum. If at step 50 the iteration is not zero, such as will occur with the loop iteration explained below, the process continues to step 54 to set the display panel brightness to minimum. From steps 52 or 54, the process continues to step 56 to switch from manually-selectable brightness settings to management of brightness by the ALS. At step 58, the current brightness setting is read as commanded by the ALS and assigned a variable of b0 for the first iteration and b1 for the second iteration. At step 60 a determination is made of whether the iteration is equal to one. If not, the process continues to step 62 to set the iteration value to one and back to step 48 to complete the second iteration of the loop. If at step 60 the iteration value is one, then values exist for both b0 and b1 and the process continues to step 64 to compare the values of b0 and b1. If the comparison at 64 indicates a difference between b0 and b1 that is greater than a predetermined value, the process continues to step 66 to indicate a bad ambient light sensor. If the comparison at step 64 shows that the values of b0 and b1 are substantially the same, the process continues to step 68 to indicate a good ambient light sensor.

Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An information handling system comprising: a housing;plural processing components disposed in the housing and operable to generate visual information for presentation at a display;a display integrated with the housing and interfaced with the processing components, the display operable to present the visual information at plural manually-selectable brightness levels;an ambient light sensor interfaced with the display, the ambient light sensor operable to detect ambient light proximate the display and to automatically adjust the display brightness level in response to the detected ambient light; anda testing module interfaced with the display and the ambient light sensor, the testing module operable to test ambient light sensor automatic brightness adjustments by comparing the ambient light sensor brightness adjustments from first and second manually-selectable brightness levels.

2. The information handling system of claim 1 wherein the first and second manually-selectable brightness levels comprise a maximum manually-selectable brightness level and a minimum manually-selectable brightness level.

3. The information handling system of claim 1 wherein comparing the ambient light sensor brightness adjustments from first and second manually-selectable brightness levels further comprises: automatically setting the display brightness at the first manually-selectable brightness level;automatically engaging the ambient light sensor;determining a first brightness level set by the ambient light sensor;automatically setting the display brightness at the second manually-selectable brightness level;automatically engaging the ambient light sensor;determining a second brightness level set by the ambient light sensor; anddetermining a difference between the first and second brightness levels set by the ambient light sensor.

4. The information handling system of claim 3 wherein comparing the ambient light sensor brightness adjustments from first and second manually-selectable brightness levels further comprises: determining that the difference between the first and second brightness levels is less than a predetermined amount; andissuing an ambient light sensor pass from the test module.

5. The information handling system of claim 3 wherein comparing the ambient light sensor brightness adjustments from first and second manually-selectable brightness levels further comprises: determining that the difference between the first and second brightness levels is greater than a predetermined amount; andissuing an ambient light sensor fail from the test module.

6. The information handling system of claim 5 wherein the testing module is further operable to communicate the ambient light sensor fail to a network location.

7. The information handling system of claim 1 wherein the processing components comprise an embedded controller and the testing module comprises firmware running on the embedded controller.

8. The information handling system of claim 1 wherein the processing components comprise a chipset supporting a BIOS and the testing module comprises firmware running in the BIOS.

9. The information handling system of claim 1 wherein the processing components comprise an inverter having a microcontroller, the inverter setting the brightness of the display, and wherein the testing module comprises firmware running on the inverter microcontroller.

10. A method for testing an information handling system display ambient light sensor, the method comprising: setting the display brightness at a first manually-selectable brightness level;engaging the ambient light sensor;determining a first brightness level set by the ambient light sensor;setting the display brightness at a second manually-selectable brightness level;engaging the ambient light sensor;determining a second brightness level set by the ambient light sensor; anddetermining a difference between the first and second brightness levels set by the ambient light sensor.

11. The method of claim 10 further comprising: determining that the difference between the first and second brightness levels is less than a predetermined amount; andpassing the ambient light sensor.

12. The method of claim 10 further comprising: determining that the difference between the first and second brightness levels is greater than a predetermined amount; andfailing the ambient light sensor.

13. The method of claim 12 further comprising communicating the failing to a network location.

14. The method of claim 10 wherein the first brightness level comprises a maximum brightness setting and the second brightness level comprises a minimum brightness setting.

15. The method of claim 10 wherein the ambient light sensor manages brightness at a portable information handling system liquid crystal display.

16. A system for testing an ambient light sensor managing brightness of a display, the system comprising: a brightness selector operable to set the display brightness to first and second brightness settings;a brightness setting detector operable to detect the brightness set by the ambient light sensor; anda testing module interfaced with the brightness selector and the brightness setting detector, the testing module operable to compare ambient light sensor brightness adjustments from the first and second brightness levels.

17. The system of claim 16 wherein the testing module compares the ambient light sensor brightness adjustments from the first and second brightness levels by: automatically setting the display brightness at the first brightness setting;automatically engaging the ambient light sensor;determining a first brightness set by the ambient light sensor;automatically setting the display brightness at the second brightness level;automatically engaging the ambient light sensor;determining a second brightness set by the ambient light sensor; anddetermining a difference between the first and second brightnesses set by the ambient light sensor.

18. The system of claim 17 wherein the brightness selector first and second brightness settings comprise a maximum manually-selectable brightness and a minimum manually-selectable brightness.

19. The system of claim 17 wherein the testing module passes the ambient light sensor if the difference between the first and second brightnesses set by the ambient light sensor are greater than a predetermined amount.

20. The system of claim 17 wherein the testing module fails the ambient light sensor if the differences between the first and second brightnesses set by the ambient light sensor are less than a predetermined amount.