[gentoo-user] edid problems

[Jack <ostroffjh@users.sourceforge.net>]

While following the "New machine: Contents of display are offset around  
2 inches from the left hand side." thread, I thought I would try  
get-edid myself.  Unfortunately, I get

This is read-edid version 3.0.2. Prepare for some fun.
Attempting to use i2c interface
Looks like no busses have an EDID. Sorry!
Attempting to use the classical VBE interface
mmap /dev/zero: Operation not permitted
error initialising realmode interface
do you have full superuser (root) permissions?
I'm sorry nothing was successful. Maybe try some other arguments
if you played with them, or send an email to Matthew Kern  
<pyrophobicman@gmail.com>.
Partial Read... Try again

Lots of searching led me to try

$sudo mount -o remount,exec /dev

which seemed to work, maybe.  Now I get

This is read-edid version 3.0.2. Prepare for some fun.
Attempting to use i2c interface
Looks like no busses have an EDID. Sorry!
Attempting to use the classical VBE interface

         Performing real mode VBE call
         Interrupt 0x10 ax=0x4f00 bx=0x0 cx=0x0
         Function unsupported
         Call failed

         VBE version 0
         VBE string at 0x0 "O�"

VBE/DDC service about to be called
         Report DDC capabilities

         Performing real mode VBE call
         Interrupt 0x10 ax=0x4f15 bx=0x0 cx=0x0
         Function unsupported
         Call failed

Reading next EDID block

VBE/DDC service about to be called
         Read EDID

         Performing real mode VBE call
         Interrupt 0x10 ax=0x4f15 bx=0x1 cx=0x0
         Function unsupported
         Call failed

The EDID data should not be trusted as the VBE call failed
Error: output block unchanged
I'm sorry nothing was successful. Maybe try some other arguments
if you played with them, or send an email to Matthew Kern  
<pyrophobicman@gmail.com>.
Partial Read... Try again

However, xrandr works fine, showing me

DisplayPort-0 connected primary 2560x1440+0+0 (normal left inverted  
right x axis y axis) 597mm x 336mm
    2560x1440     74.60*+  59.95
....
HDMI-A-0 connected 2560x1440+2560+0 (normal left inverted right x axis  
y axis) 597mm x 336mm
    2560x1440     74.60*+  59.95
....
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)

(where the .... are 18 other modelines.)

My monitors work fine, but I'm curious why get-edid is failing.

My mobo is
   MSI B50 Tomahawk
and my GPU is
   VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]  
Cape Verde XT [Radeon HD 7770/8760 / R7 250X].

Any thoughyts or suggestions?

Thanks.

Jack