[HARDWARE MOD] Intel-IGP/Optimus based Clevo screen overclocking (P150SM tested)

[tmash]

Hello earth,

WARNING: although this is a semi-guide, what you're about to read isn't for the faint hearted XD, I'm not responsible for any damage, fire, death to your pet etcetera if you attempt to do it...

As you may already know, you cannot force custom timings on intel igps, unlike dGPU system only, since Intel IGP cannot do EDID overrides. More about EDID: https://en.wikipedia.org/wiki/Extended_Display_Identification_Data

The solution was to dump the EDID which can be done using modeline in windows registry, linux modeline, or dumping directly from the EEPROM (electrically erasable read only memory found physically in most screen logic) which should be straightforward as we need to actually reflash it with our modification simply over i2c interface using arduino (simple 328 with serial-to-usb, can be from 8$ to 25$ max) you can also buy an EEPROM programmer which can be slightly expensive.

The screen I have is a CMN1B, Chi .

Should also work with AOU 95% gamut screen, any screen with i2c interface to eeprom, you can actually trace it along the 18th and 19th pin from the LVDS cable, however it should be pretty visible.

So I ended up (easily), disassembling the screen as per this guide: [GUIDE] How to replace an LCD panel on a Clevo shell (pictures included) | NotebookReview

I've then cut the film from both sides then taped for making it easier to work (i.e: instead of cutting EEPROM's pin location):

There are 2 EEPROMS in my case, identified it simply by looking at the test point tagging, EE_SC SD etc, should be similar in any other displays:

Tip size reference, basically any 15 to 30 watts soldering iron should work, unless the testpoints are tiny on other displays like AUO, though it is least likely you will ever have to desolder the EEPROM chip:

Sold'er! Roger that(You can see the EE_* tags, SC for clock, and D for data etc):

Connect to my Duino(wire it as you normal i2c):

My EDID dumped in Linux before proceding to flash:

 

    EDID: 
        00ffffffffffff000daeb11500000000
        01160104902213780231d59f56589527
        15505400000001010101010101010101
        010101010101963b803271383e405a3c
        690058c21000001a9b2580ee70382340
        3523350058c21000001a000000fe0056
        434d3858024e31353648470a00000000
        000041319e0000000002010a20200005
    BACKLIGHT: 133 
        range: (0, 976)
    Backlight: 133 
        range: (0, 976)
    scaling mode: Full aspect 
        supported: None, Full, Center, Full aspect
    Broadcast RGB: Automatic 
        supported: Automatic, Full, Limited 16:235
    audio: auto 
        supported: force-dvi, off, auto, on
  1920x1080 (0x4c)  152.5MHz +HSync -VSync *current +preferred
        h: width  1920 start 2010 end 2070 total 2226 skew    0 clock   68.5KHz
        v: height 1080 start 1086 end 1095 total 1142           clock   60.0Hz

 

Pasted in Deltacast EDID editor then modified Pixel clock from 152 mhz (60hz calculated in DTD calculator) to 209 mhz, you have to calculate by entering these from the upper code repecitevly from top to bottom

 

920x1080 (0x4c)  152.5MHz +HSync -VSync *current +preferred
        h: width  1920 start 2010 end 2070 total 2226 skew    0 clock   68.5KHz
        v: height 1080 start 1086 end 1095 total 1142 

 

Export the modifications in EDID editor as hex, make sure you add 60hz(original mod) in block 3 so you can switch between 40 60 120, then using find&replace method modify the format according to the next step

Then modify the array in the code (acc to format, 0x and ,) upload to arduino: https://learn.adafruit.com/adafruit-tfp401-hdmi-slash-dvi-decoder-to-40-pin-ttl-display/editing-the-edid

I'v managed to go up to 120hz stable, yours may be different although the same model number...

 xrandr output at 85hz:

Had to reboot twice on Windows under UEFI boot manager in order to recognize the 120hz option, weird

Again, this is not a thorough guide, just sharing my experience. It went pretty straightforward, and simple as a typical EDID modding over VGA cable or DVI.

Edited April 2, 2016 by tmash

[Khenglish]

Decent results. I overclocked 3 95% gamut screens with max of 78, 87, and 94 Hz.

[jaybee83]

great work, very nice im stuck at max. 65 hz *sigh* [emoji14]

Sent from my Nexus 5 using Tapatalk

[Alibi]

Can someone help me how to do it on a P157SM?  I am a total noob for now.