lcd panel edid eeprom error in stock

I"m faced with an interesting issue! One of our client Dell laptop does not show POST/Dell splash screen when powered on. Eventually, after a minute or two, the Windows login screen appears. I"ve replaced the LCD panel, updated BIOS, drained power, reseated everything possible, and even re-imaged the HD. Dell diagnostics gives me this error: LCD EDID - Unable to access EDI EEPROM, even after replacing the LCD panel. I"m beginning to suspect that the motherboard is the culprit here. Anyone seen this type of issue before?Just out of curiosity, what does Dell Support have to say about that error?

I"m faced with an interesting issue! One of our client Dell laptop does not show POST/Dell splash screen when powered on. Eventually, after a minute or two, the Windows login screen appears. I"ve replaced the LCD panel, updated BIOS, drained power, reseated everything possible, and even re-imaged the HD. Dell diagnostics gives me this error: LCD EDID - Unable to access EDI EEPROM, even after replacing the LCD panel. I"m beginning to suspect that the motherboard is the culprit here. Anyone seen this type of issue before?Just out of curiosity, what does Dell Support have to say about that error?

SOLVED! I replaced the LVDS cable, and I am now able to see the Dell splash screen and also access BIOS and PXE boot. Diagnostics no longer reports an error. It"s a beautiful day - birds are chirping, flowers are blooming, people are happy. Thank you all for the support!!!

The 24C04 is a 4K Bit EEPROM used to store monitor display control data. This memory is not directly accessible by the consumer; the adjustments are entered into the OSD menu, then the MCU writes the new data to the EEPROM. The information stored in the EEPROM is limited to specific parameters controlled by the monitor MCU.

The 24C02 is a 2K Bit EEPROM used to store monitor EDID information for use by the host PC. This information is written at the factory, and cannot be altered or deleted by the consumer.

The trouble started when I activated Intel"s integrated, on-board graphics controller. I connected the digital output and made it the primary adapter in the BIOS. The screen remained dark. I switched monitors around and realized why: The EDID from the digital input was broken.

After some research, I realized that EDID issues are actually fairly common. The EEPROMs used to store the information are not always write-protected. Some people say hot-plugging the cables can cause corruption.

First off, let me mention that the Linux kernel has a great way to deal with the issue. It can load EDID information on a non-permanent basis like firmware via the kernel command line. In my case, I included the EDID file in the initrd and reconfigured my bootloader with:

It worked great! I simply used the EDID data from the analog input, even though monitors present slightly different EDID data on their analog and digital inputs. I am not sure why or when it matters.

Going through these steps with the kernel is good for two reasons. Firs, it shows you if the EDID you are about to flash actually makes your monitor perform better. (Without EDID data, most systems offer only lower VESA resolutions.) Second, it will give you confidence that there is an acceptable backup solution in case you break the EEPROM, although I think that particular risk is small.

All monitor connectors, such as VGA, DVI and HDMI, have dedicated pins that do nothing but read the EDID information from monitors. They use the I2C protocol. It was designed for serial communications between integrated circuits. All graphics cards can read this bus, and many can write to it.

For example, I successfully overwrote the digital EDID for my ViewSonic monitor with the analog version, but it ended up not working. In retrospect, it was probably a cabling issue (more on that later) but I chose to restore the original digital version, which was surprisingly easy.

You can use cat to store each piece of information in a separate file. I inspected the files with parse-edid and wxedid and gave them meaningful names such as:

Please do not forget to switch your cables around to get the other inputs also. For each monitor that is fully functional you should have two EDID files—one for the analog and another for the digital input.

The method above seems to work only for the EDID that were recognized as valid. For any others (and hopefully it is just one) we will use the eeprom driver:

The folder contains a bunch of devices and buses but we only care about those with a start offset of 0x50. The data is similar to the edid data above, but here you get the actual hardware contents. In my case, all monitors used 256 byte EEPROMS.

Once again I used cat to save the data returned by each of the eeprom devices. Unlike the EDIDs, which can be of variable length, all data here was 256 bytes long (although all higher bytes were empty).

Use tools like parse-edid, hexdump or wxedid to figure out which eeprom corresponds to the broken EDID. (You may have to tell wxedid to ignore the checksum.) Make a copy of the broken file.

An early version of the service manual for my monitor stated that both analog and digital EDIDs were identical. Initially, simply programmed the working analog data into the broken digital input. Still, the monitor was not recognized on reboot (although I now think it was a cabling issue). That is how I ended up patching the digital file.

I opened up two instances of wxedid. One was for the working and another for the broken EDID, respectively. (Again, you may have to tell the program to ignore the checksum on the broken file.) I then adjusted a few parts of the broken digital data to look more like the working analog copy.

When I asked wxedid to compute the checksum—hey presto—it matched the existing record. The data I added probably restored the EDID to what it was once. I used wxedid to save it as a *.bin file. The length was 128 bytes long, which was what I expected.

Some of the hexdumps can look a little different from one to another. In my case, some were on a byte basis, while another used two-byte words. Just make sure you are looking at the same thing. Again, the broken EDID should be in the bus number you memorized above.

Writing to EEPROMs is a very dangerous operation. You can literally destroy your computer. You just have to write to the wrong place, or perhaps write too much data. There is particular risk with your DRAM chips.

Serious EEPROM programmers should use other software options instead. The i2c-tools maintainers only ship a version that changes a single byte, but it is enough for us.

Finally, please verify with i2cdump that the EEPROM contains the correct data now. Reboot to see if your BIOS and the Linux kernel agree with your assessment.

In my case, I encountered a vexing problem. Even though the data in the EEPROM was clearly correct, neither the BIOS nor the kernel accepted the first EDID during reboots (and dmesg showed it was defective).

Features1. You can program notebook LCD EDID with standart programmer set 24c02 eeprom.2. It"s designed for writing and reading EDID EEPROM in LED ans LCD 30 and 40 pin3. You can fix whitescreen error and brightness control errors - reading the firmware with the old broken matrix and writing it in a new.4. You can use it with TL866CS, EZP2010, Skypro and many others EEPROM programmersPackage includes1 x Screen Code Chip Data Read LineHow to use, for reference only, the LCD and programmer does not includes.

EDID data exchange is a standardized means for a display to communicate its capabilities to a source device. The premise of this communications is for the display to relay its operational characteristics, such as its native resolution, to the attached source, and then allow the source to generate the necessary video characteristics to match the needs of the display. This maximizes the functional compatibility between devices without requiring a user to configure them manually, thus reducing the potential for incorrect settings and adjustments that could compromise the quality of the displayed images and overall reliability of the system.

Generally, the source device will be a computer graphics card on a desktop or laptop PC, but provisions are in place for many other devices, including HDTV receivers and DVRs, DVD and Blu-ray Disc players, and even gaming consoles, to read EDID and output video accordingly. Originally developed for use between analog computer-video devices with VGA ports, EDID is also now implemented for DVI, HDMI, and DisplayPort.

EDID was developed by VESA - the Video Electronics Standards Association, with version 1.0 introduced in 1994 within version 1.0 of the DDC standard. See Table 1.

Prior to the development of EDID, pins 4, 11, 12, and 15 on the VGA connector were sometimes used to define monitor capabilities. These ID bit pins carried either high or low values to define different screen resolutions. VESA extended this scheme by redefining VGA connector pins 9, 12, and 15 as a serial bus in the form of the DDC - Display Data Channel. This allowed for much more information to be exchanged, so that EDID and other forms of communication were possible between the source and the display.

As display types and capabilities increased, 128 bytes became insufficient, and both EDID and DDC were extended so that multiple 128-byte data blocks could be exchanged. This is known as E-EDID and has been implemented in many consumer devices. In fact, the CEA - Consumer Electronics Association has defined its own EDID extensions to cover additional video formats and to support advanced multi-channel audio capabilities.

In December 2007, VESA released DisplayID, a second generation of EDID. It is intended to replace all previous versions. DisplayID is a variable length data structure, of up to 256 bytes, that conveys display-related information to attached source devices. It is meant to encompass PC display devices, consumer televisions, and embedded displays such as LCD screens within laptops, without the need for multiple extension blocks. DisplayID is not directly backward compatible with previous EDID/E-EDID versions, but is not yet widely incorporated in AV products.

The base EDID information of a display is conveyed within a 128-byte data structure that contains pertinent manufacturer and operation-related data. See Table 2. The current EDID version defines the structure as follows:

The general structure of CEA-861 extension data is shown in Table 3. CEA-861 allows for a variable number of 18-byte detailed timing descriptions to be included. For example, video timing details for 1080i, which is popular for consumer displays but not for PCs, can be communicated. CEA-861 also specifies a variable length "CEA Data Block Collection" for describing parameters such as display colorimetry, and advanced audio capabilities including surround sound format, audio sampling rate, and even speaker configuration and placement. The significance of the CEA-861 extension is that it aims to address previous operational disparities experienced with integrating consumer-based display devices into computer-based commercial AV systems, allowing for proper conveyance of EDID information between devices.

EDID information is typically exchanged when the video source starts up. The DDC specifications define a +5V supply connection for the source to provide power to a display"s EDID circuitry so that communication can be enabled, even if the display is powered off. At startup, the video source will send a request for EDID over the DDC. The EDID/DDC specifications support hot plug detection, so that EDID information can also be exchanged whenever a display is reconnected to a video source. Hot plug detection is not supported for VGA, but is supported in digital interfaces including DVI, HDMI, and DisplayPort. For these interfaces, the display device will supply a voltage on an HPD - Hot Plug Detect pin, to signal to the video source device that it is connected. The absence of a voltage on the HPD pin indicates disconnection. The video source device monitors the voltage on the HPD pin and initiates EDID requests as it senses incoming voltage.

Display devices can have various levels of EDID implementation and, in some cases, they may lack EDID information altogether. Such inconsistencies can cause operational issues ranging from overscan and resolution problems, to the display device not displaying the source content at all.

Possible CauseThe source device, such as a PC graphics card, or laptop, cannot read the EDID information from the display. As a result, in some cases the PC will not output any video signal.

While hot plug detection is supported for DVI, HDMI, and DisplayPort, EDID communication problems can arise from inconsistencies in the implementation of HPD signaling between devices from different manufacturers. This frequently becomes an issue for professional integration, since the ability to switch digital video signals is a necessity.

Possible CauseA PC cannot read the EDID information, so it defaults to a standard resolution, such as 640x480. If the user subsequently attempts to manually set the resolution to match the display, some graphics card drivers may enforce the lower default resolution and create a scrolling/panning desktop without actually changing the video resolution.

The PC is able to read the EDID information, but the graphics card limits the output resolution to XGA 1024x768, a resolution most displays can accommodate, ensuring a usable image and reducing the likelihood of no image being displayed. If this does not match the native resolution of the display, fonts will likely appear to be abnormally large, small, or fuzzy.

The PC is connected to multiple displays with different native resolutions. Since it can only read EDID from one display, the output will be mismatched in resolution with all other displays, resulting in less than optimal image quality, or no image displayed at all. This issue is a common occurrence in professional systems when video signals need to be distributed or routed to multiple displays.

Software such as Extron EDID Manager can be used to help troubleshoot possible compatibility issues between the display device and the source. EDID Manager is available as a free download from Extron"s Web site, www.extron.com. It is a useful software tool that allows you to read the display"s EDID and determine whether a graphic card and the display device may be experiencing EDID handshake problems.

AV systems typically comprise several remotely located displays and often include multiple source devices. It is important to realize this can potentially contribute to EDID-related issues. The necessity to switch, distribute, and route signals from sources to displays presents a considerable challenge in terms of ensuring proper EDID communications and therefore reliable system operation.

For example, systems that employ RGBHV-based distribution have no means of passing EDID information from the display to the source. This could become problematic in system designs where laptops and computers with expectation of seeing EDID are connected into the system. Since EDID information is not being provided to these devices, some of the aforementioned EDID communication issues may occur.

Extron products include features to help prevent or solve many of them by properly managing EDID communications between sources and displays in AV systems. These features provide automatic and continuous EDID management with attached source devices, ensuring proper power-up and reliable output of content.

EDID Emulation is a feature of many Extron DVI and HDMI products, including switchers, distribution amplifiers, and matrix switchers. It maintains constant EDID communication with source devices by providing pre-stored EDID information for various signal resolutions. A user can select the desired signal resolution, and then the corresponding EDID block is conveyed to all attached source devices. This EDID information is constantly available to the sources, even in a switching application where inputs are regularly selected and de-selected. The output of the sources should match the native resolution of the intended display device.

EDID Minder® is an advanced, Extron exclusive technology for EDID management. It encompasses EDID Emulation, but also incorporates an additional level of "intelligence." Extron products with EDID Minder® can communicate with the display device, and automatically capture and store EDID information from the display. See Figure 3. This captured information can then be used as the reference EDID for the sources. EDID Minder® is a standard feature in most Extron DVI and HDMI extenders, switchers, distribution amplifiers, and matrix switchers, as well as products that incorporate DVI or HDMI switching.

The functional role of a given product as a distribution amplifier, switcher, or matrix switcher determines the complexity of EDID Minder® implementation. Matrix switching environments represent the most difficult EDID management situation, with simultaneous EDID communications required for multiple inputs and outputs. The displays connected to the outputs are very likely to be of different models and native resolutions. The EDID information between them is different and needs to be conveyed to the source devices. Proper EDID management within the system is crucial to consistent and reliable operation.

Extron HDMI and DVI matrix switchers with EDID Minder® achieve this by managing EDID communications for each input/output tie. EDID Minder® first analyzes the EDID for all displays connected to the system, applies a complex algorithm to determine a common resolution, refresh rate and color space, and then uses the EDID protocol to set up the input sources. This powerful convenience feature simplifies system setup for the integrator, helps ensure consistent and reliable image display, and makes system operation virtually transparent to the end user.

A method of changing EDID of a memory of a motherboard in response to replacing an LCD panel of a computer with a different one comprises detecting a chipset; reading a SM bus base or GPIO base; activating a writing mechanism; selecting compatible EDID; writing the EDID into the memory; detecting an error; and closing the writing mechanism. The invention can be embodied by means of software rather than hardware. Thus, it is much convenient.

The present invention relates to method of changing settings of a motherboard and more particularly to a method of changing an EDID (extended display identification data) stored in memory of a motherboard by means of software rather than hardware in response to replacing an LCD (liquid crystal display) panel of a computer with a different one.

Conventionally, an LCD panel of computer has a unique EDID which is defined by VESA (Video Electronic Standards Association) standard. Electrical characteristics of an LCD panel are stored in EDID. EDID is a protocol of DDC (display data channel) for enabling a computer to correctly identify specifications of the LCD panel for control. EDID is typically stored in an EEPROM (electrically erasable programmable read-only memory) of a motherboard. This means that EDID is unique to each motherboard. Thus, the motherboard and thus the computer may not function normally if the original LCD panel is replaced by a new one of different brand. For solving this problem, the only method is to remove the EEPROM from the motherboard prior to burning in a compatible EDID into the EEPROM. Further, it is required to remove the EEPROM from the motherboard prior to burning in changed parameters of EDID into the EEPROM if parameters of LCD panel are required to change. In view of the above, it is not convenient. Hence, a need for improvement exists. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method of changing EDID of a memory of a motherboard in response to replacing an LCD panel of a computer with a different one, comprising the steps of detecting a chipset; reading a SM bus base or GPIO (General Purpose Input Output) base; activating a writing mechanism; selecting compatible EDID; writing the EDID into the memory; detecting error; and closing the writing mechanism.

Referring to FIG. 1, a LCD VGA (Video Graphics Array) controller of the invention accesses EDID of a desired LCD via a SM (system management) bus (or I2C bus) of DVOI (Digital Video Output Interface) and a selector. As such, initialization data for illuminating LCD panel can be obtained. Hence, different LCD panels can be controlled by changing EDID with respect to factors such as brightness adjustment, etc.

Referring to FIG. 2, there is shown a process of the invention. The process comprises the steps of detecting a chipset for determining whether it is VIA 686B or Intel 815 (step 21); reading SM bus base or GPIO (General Purpose Input Output) base (step 22) if the determination step is positive else ending the process; activating a writing mechanism if the reading is correct (step 23); selecting compatible EDID (step 24); writing EDID into EEPROM (step 25); detecting error (step 26) if the writing is correct; and closing the writing mechanism (step 27) prior to ending the process.

Referring to FIG. 3, there is shown a screen of the invention. As shown, a predetermined number of ID files are available to select on the screen. The ID files comprise standard 640*480 pixels (31), standard 800*600 pixels (32), standard 1024*768 single and dual pixels (33 and 34), and others for selecting a bin file (35). The process of the invention will store EDID in memory (e.g., EEPROM) if the selected EDID is compatible with that of the LCD panel. Referring to FIG. 4, stored filenames and associated information are shown on the screen. EDID comprises a number of parameters adapted to change. For example, a maximum horizontal image size is defined in address 15 h, and Gamma value to be transmitted is defined in address 17 h. These parameters are recorded in a bin file. Changes of the parameters can be carried out by editing the bin file and clicking the others (35) option of the above screen to write the changed EDID.

In brief, the invention can carry out a method of changing an EDID stored in memory of a motherboard by means of software rather than hardware if the original LCD panel is replaced by a new one of different brand. As an end, a plug and display feature can be obtained.

1. A method of changing EDID of a memory of a motherboard in response to replacing an LCD panel of a computer with a different one, comprising the steps of:

Does anybody happen to have a full EEPROM dump (4 KB) for the AUO B156HTN03.8 LED panel? I"d need not only the EDID part (first 128 bytes), but also the rest of the LCD FW, which seems to be located on the same EEPROM chip as the EDID but from offset 0x100.

Interestingly, it seems as though the EEPROM was "randomly" overwritten at offsets 0x0, 0x100 and 0x200 with some garbage data of ca 15-16 bytes. Could be, that the previous owner had removed the connector, while still under power and thus wiping some EEPROM address areas with garbage...

The panel does light up and changes the backlight, but only with a black screen with no picture. I wonder if those wiped areas within the FW might contain the detailed timing infos needed to provide the right timing data.

However on my Lenovo laptop these "files" were empty, perhaps they"re different on your system. I found this forum thread that showed sample output from the VGA EDID.