Created attachment 642307 [details]
Xorg.0.log

Description of problem:
My system knows what is the true screen size through EDID. Intel driver knows this as well (which is confirmed in Xorg.0.log), but still, it is overriding this setting with no good reason (with line: "Setting screen physical size to"). 

This makes fonts too tiny too read. True DPI of the screen should be 130 x 130, while my X server starts with 96 x 96. I couldn't find any way to fix this.
Gimp thinks it is 96 DPI, xdpyinfo thinks the screen size is wrong, hence dpi is wrong - or vice versa. Xrandr knows the good value of the screen size, but is it not used by X server to display fonts and web pages right. I need big glasses to use computer now.

In details. Every time X starts, card recognizes true physical size properly:
  ...
  [    22.820] (II) intel(0): EDID for output LVDS1
  [    22.820] (II) intel(0): Manufacturer: AUO  Model: 213e  Serial#: 0
  [    22.820] (II) intel(0): EDID Version: 1.4
  ...
  [    22.820] (II) intel(0): Max Image Size [cm]: horiz.: 31  vert.: 17
  [    22.820] (II) intel(0): Gamma: 2.20
  ...
(with the ruler I measured it to be exactly 31.1 cm x 17.5 cm)
Then the size is confirmed in this lines:
  ...
  [    22.820] (II) intel(0): Supported detailed timing:
  [    22.820] (II) intel(0): clock: 110.0 MHz   Image Size:  309 x 174 mm
  [    22.820] (II) intel(0): h_active: 1600  h_sync: 1664  h_sync_end 1706 h_blank_end 2010 h_border: 0
  [    22.820] (II) intel(0): v_active: 900  v_sync: 903  v_sync_end 906 v_blanking: 912 v_border: 0
  [    22.820] (II) intel(0): Supported detailed timing:
  ...
  [    22.920] (II) intel(0): Using exact sizes for initial modes
  [    22.920] (II) intel(0): Output LVDS1 using initial mode 1600x900 +0+0
  ...
Next DPI is calculated properly by the intel driver (I am guessing):
  ...
  [    22.920] (**) intel(0): Display dimensions: (310, 170) mm
  [    22.920] (**) intel(0): DPI set to (131, 134)
  ...
Finally, image size is OVERRIDED by the intel driver with no explanation. It is set to wrong value:
  ...
  [    22.968] (II) AIGLX: Loaded and initialized i965
  [    22.968] (II) GLX: Initialized DRI2 GL provider for screen 0
  [    22.969] (II) intel(0): Setting screen physical size to 423 x 238
  [    23.036] (II) XKB: Reusing cached keymap
  ...
And this sucks. I cannot imagine how the X server would look like on a laptop with retina display, because of this bug.

Version-Release number of selected component (if applicable):
Name        : xorg-x11-drv-intel
Arch        : i686
Version     : 2.20.10
Release     : 2.fc17

  
Actual results:
Fonts are too small. Other thinks look tiny as well. Need glasses.

Expected results:
DPI should be set to reflect actual size of the screen

Additional info:
There is similar Bug #840271 reported for xorg-x11 in F16 with Nvidia card. It is possible that the issue is intrinsic to GNOME Shell or Cinnamon, which I am using or X11. There is also similar bug #863669 reported for RHEL's xorg-x11-server with laptop with NVidia card. But these bugs do not mention nor cite the line: "Setting screen physical size to" which I think is essential. They mention only the fact that xrandr and xdpyinfo give different results.

Also, I did corrected the entry in /etc/X11/Xresources
from:
  Xft.dpi: 96
to:
  Xft.dpi: 130
But this did not help at all.