Created attachment 5342 
Fix mode validity determination by checking display resolution dimensions instead of mode name and using 1/10 Hz precision for rate comparison

I've got a monitor that gets assigned an unsupported mode from EDID information by the X-Server (output from xrandr):

  1280x1024 (0x57)  108.0MHz +HSync +VSync
        h: width  1280 start 1328 end 1440 total 1688 skew    0 clock   64.0KHz
        v: height 1024 start 1025 end 1028 total 1066           clock   60.0Hz

So in xorg.conf I manually defined a working mode:

  1280x1024R (0x5d)   90.8MHz +HSync -VSync +preferred
        h: width  1280 start 1328 end 1360 total 1440 skew    0 clock   63.0KHz
        v: height 1024 start 1027 end 1034 total 1054           clock   59.8Hz

This mode I can set manually using xrandr:

  xrandr --output DVI-0 --mode 1280x1024R

But it is not possible to set this mode in the xfce4-display-settings (these modes can be distinguished by 60 Hz vs. 59.8 Hz), because the newly defined mode has a name '1280x1024R' that does not correspond to the pattern '<W>x<H>' which xfsettingsd implicitely assumes (xfsettingsd/displays.c:697):

            /* find the mode corresponding to the saved values */
            if (rint (rate) == rint (output_rate)
                && (g_strcmp0 (helper->resources->modes[m].name, str_value) == 0))
            {
                valid_mode = helper->resources->modes[m].id;
                break;
            }

So the attached patch changes the string-comparison to comparing the derived integer values for width/height. It also changes the precision of the rate comparison from 1 Hz to 1/10 Hz to match the precision that xfce4-display-settings offers in its rate-combobox.