HDMI on the BBB

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[edit] Overview

Discussion of HDMI on the BBB.

[edit] Links

[edit] Getting EDID info on your BBB

The 256 bytes of monitor EDID information is brought out in the sysfs file /sys/class/drm/card0/card0-HDMI-A-1/edid, and you can view it on your BBB with:

# xxd /sys/class/drm/card0/card0-HDMI-A-1/edid

[edit] Experimenting with my ASUS VE228H

This is the monitor I'm using and, currently, the desktop is almost perfect but for a slight but noticeable left-to-right jitter.

The EDID information is:

# xxd edid
0000000: 00ff ffff ffff ff00 0469 fa22 0101 0101  .........i."....
0000010: 1c16 0103 8030 1b78 ea3d 25a3 5951 a025  .....0.x.=%.YQ.%
0000020: 0f50 54bf ef00 714f 8180 8140 9500 a940  .PT...qO...@...@
0000030: b300 d1c0 0101 023a 8018 7138 2d40 582c  .......:..q8-@X,
0000040: 4500 dd0c 1100 001e 0000 00fd 0032 4c1e  E............2L.
0000050: 5311 000a 2020 2020 2020 0000 00fc 0056  S...      .....V
0000060: 4532 3238 0a20 2020 2020 2020 0000 00ff  E228.       ....
0000070: 0043 374c 4d51 5330 3338 3638 350a 014d  .C7LMQS038685..M
0000080: 0203 1ef1 4b90 0504 0302 0111 1213 141f  ....K...........
0000090: 2309 0707 8301 0000 6503 0c00 1000 1a36  #.......e......6
00000a0: 80a0 7038 1e40 3020 3500 dd0c 1100 001a  ..p8.@0 5.......
00000b0: 6621 56aa 5100 1e30 468f 3300 dd0c 1100  f!V.Q..0F.3.....
00000c0: 001e 011d 0072 51d0 1e20 6e28 5500 dd0c  .....rQ.. n(U...
00000d0: 1100 001e 8c0a d08a 20e0 2d10 103e 9600  ........ .-..>..
00000e0: dd0c 1100 0018 011d 8018 711c 1620 582c  ..........q.. X,
00000f0: 2500 dd0c 1100 009f 0000 0000 0000 0032  %..............2
#

If I copy that to my Ubuntu host, I can parse that to see:

$ parse-edid < edid
parse-edid: parse-edid version 2.0.0
parse-edid: EDID checksum passed.

        # EDID version 1 revision 3
Section "Monitor"
        # Block type: 2:0 3:fd
        # Block type: 2:0 3:fc
        Identifier "VE228"
        VendorName "ACI"
        ModelName "VE228"
        # Block type: 2:0 3:fd
        HorizSync 30-83
        VertRefresh 50-76
        # Max dot clock (video bandwidth) 170 MHz
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:ff
        # DPMS capabilities: Active off:yes  Suspend:yes  Standby:yes

        Mode    "1920x1080"     # vfreq 60.000Hz, hfreq 67.500kHz
                DotClock        148.500000
                HTimings        1920 2008 2052 2200
                VTimings        1080 1084 1089 1125
                Flags   "+HSync" "+VSync"
        EndMode
        # Block type: 2:0 3:fd
        # Block type: 2:0 3:fc
        # Block type: 2:0 3:ff
EndSection
$


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