On my Salix (slackware 13.37 derivative) xrandr zoom works OK but xrandr with panning only works for a little while. Then the system freezes. I want to get back to the status I had in previous versions of Slackware, where a simple change to xorg provided both the zoom and the pan facilities. You could change the zoom with a simple <>ctl><alt><+> sequence. Unfortunately Slack 13.37 does not have a file named xorg.conf but rather a directory called xorg.conf.d and additions to that directory don't restore either the zoom or pan features.
I can't go back to earlier versions of Slackware because essential software requires Qt4 and my attempts to have both Qt3 and Qt4 on the same partition have not been successful.