Wrong DPI calculation
Submitted by Nico R.
Assigned to Xorg Project Team
On a computer using xorg-7.4 with xorg-server-1.6.0, xf86-video-intel-184.108.40.2062 and libXrandr-220.127.116.11 and randrproto-18.104.22.168 (do not know whether the last two are relevant), the DPI values seem to be incorrectly calculated.
The screen is 331x207 millimeters (measured and given as DisplaySize in xorg.conf). The mode set in xorg.conf is 1680x1050.
Grepping the Xorg logfile for that stuff results in the following lines:
(II) intel(0): Output LVDS using initial mode 1680x1050 () intel(0): Display dimensions: (331, 207) mm () intel(0): DPI set to (128, 206) (II) intel(0): Setting screen physical size to 331 x 207
It seems that the vertical DPI value is calculated using the horizontal resolution:
xDPI = 1680/(331/25.4) ~= 128.9 (OK) yDPI = 1050/(207/25.4) ~= 128.8 (should be that value) yDPIwrong = 1680/(207/25.4) ~= 206.1 (is that value instead)
I filed this bug for the Driver/intel component, but it may belong to Server/general (or even App/xrandr?). Someone who knows better than me should properly set the component.
This bug might also be related to bug 16789; that looks a bit different, though.
Version: 7.6 (2010.12)