View source for EDP Display Controller diagnostic: it6251-dump-dptx

==eDP Display Controller diagnostic==

it6251-dump-dptx is a utility to dump the [https://en.wikipedia.org/wiki/Extended_Display_Identification_Data EDID] information from an attached display over the DPTX channel of the IT6251 used in the eDp Adapter. This helps to determine if the display adapter is present and functional.

The source code can be found here: https://github.com/xobs/it6251-dump-dptx

Sample output, from a Novena laptop, looks like this:

 robb@novena:~/it6251-dump-dptx$ ./it6251-dump-dptx
 reg0E = 90, Link Rate = HBRreg0D = 3e,  HPD Video Stable
 frequency = 27648000, xCnt = 1
 Data Enable start: (114, 30)
 Modeline "1920x1080" 27.648  1920 2004 2050 2080  1080 1106 1108 1112 -HSync -VSync
 00000000 00 ff ff ff ff ff ff 00  0d ae 43 13 00 00 00 00  |..........C.....|
 00000010 34 15 01 04 a5 1c 10 78  02 93 ad a9 53 4c 96 25  |4......x....SL.%|
 00000020 11 4f 53 00 00 00 01 01  01 01 01 01 01 01 01 01  |.OS.............|
 00000030 01 01 01 01 01 01 36 36  80 a0 70 38 20 40 2e 1e  |......66..p8 @..|
 00000040 24 00 1a a5 10 00 00 18  00 00 00 10 00 38 20 40  |$............8 @|
 00000050 2e 1e 24 00 1a a5 10 00  00 18 00 00 00 fe 00 43  |..$............C|
 00000060 4d 4e 0a 20 20 20 20 20  20 20 20 20 00 00 00 fe  |MN.         ....|
 00000070 00 4e 31 33 33 48 53 45  2d 45 41 31 0a 20 00 95  |.N133HSE-EA1. ..|
 00000080 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 00000090 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 000000a0 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 000000b0 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 000000c0 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 000000d0 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 000000e0 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 000000f0 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

N133HSE is the model number of the Chimei Innolux LCD panel used on the laptop.

(Note that the utility can report "HPD Video Unstable" when the screen is shutdown e.g. for power saving.)