How to set HDMI to be FULL Range?

Products Support DragonBoard 820c
#1

Hi. It seems like the HDMI output is set to limited mode. My understanding (very little) about HDMI display is that there are two modes: Full and limited. Limited outputs values from 16 to 235. Full outputs values from 0 to 255. It seems like the dragonboard is in limited mode? Is there a way to switch to full mode? Some devicetree setting? Or is it always just limited. We are using linux 4.14 linaro.
This link pretty much shows what we see. White is not white. It is dull or soft.

image
image1293×373 138 KB

thanks,
Kim

#2

Would you not be able to change that via xrandr: https://wiki.archlinux.org/index.php/Intel_graphics#Weathered_colors_(color_range_problems)

#3

Hi Loic,

Thanks for the suggestion! Unfortunately that did not work for me. I get this error when I run the xrandr command:

X Error of failed request: BadName (named color or font does not exist)
Major opcode of failed request: 140 (RANDR)
Minor opcode of failed request: 11 (RRQueryOutputProperty)
Serial number of failed request: 22
Current serial number in output stream: 22

Reading about this property, it sounds like this is for and Intel graphics card:

this is my output from when running --verbose:
xrandr --verbose
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 65535 x 65535
HDMI-1 connected primary 1920x1080+0+0 (0x42) normal (normal left inverted right x axis y axis) 708mm x 398mm
Identifier: 0x40
Timestamp: 14497
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
EDID:
00ffffffffffff0020ad300001000000
241b0103807341780acf74a3574cb023
09484c21080081804540614095000101
010101010101023a801871382d40582c
4500c48e2100001e662150b051001b30
40703600c48e2100001e000000fc0048
4d5f4445560a202020202020000000fd
00324b1e5017000a20202020202001e8
02032ef24d010304050790121314169f
2022260907071117508301000070030c
001000b84420a0820102030401418c0a
d08a20e02d10103e9600c48e21000018
8c0ad090204031200c405500c48e2100
0018011d00bc52d01e20b8285540c48e
2100001e011d80d0721c1620102c2580
c48e2100009e00000000000000000095
link-status: Good
supported: Good, Bad
CONNECTOR_ID: 28
supported: 28
non-desktop: 0
supported: 0, 1
1920x1080 (0x42) 148.500MHz +HSync +VSync *current +preferred
h: width 1920 start 2008 end 2052 total 2200 skew 0 clock 67.50KHz
v: height 1080 start 1084 end 1089 total 1125 clock 60.00Hz
4096x2160 (0x43) 297.000MHz +HSync +VSync
h: width 4096 start 5116 end 5204 total 5500 skew 0 clock 54.00KHz
v: height 2160 start 2168 end 2178 total 2250 clock 24.00Hz
4096x2160 (0x44) 296.703MHz +HSync +VSync
…

Maybe my monitor does not support this property?
Thanks,
Kim