ports/183435: 100% CPU use of xorg using firefox when showing large images (say 20 Mpixel)

[W.Scholten]

>Number:         183435
>Category:       ports
>Synopsis:       100% CPU use of xorg using firefox when showing large images (say 20 Mpixel)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-ports-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Oct 29 12:00:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     W.Scholten
>Release:        10.0 B2
>Organization:
>Environment:
FreeBSD localhost 10.0-BETA2 FreeBSD 10.0-BETA2 #0 r257166: Sat Oct 26 19:23:22 UTC 2013     root at snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64

>Description:
I don't know whether this is an xorg or firefox bug or whether this happens other operating systems than fbsd. I have the same issue with fbsd 9.2R. I didn't have this issue with 9.1-RC1


The whole desktop becomes unresponsive due to xorg being at 100%. I'm running 10.0B2 and 9.2R on a machine with 8GB RAM, AMD 6 core FX6100 CPU, 10.0 B2 is installed on an SSD, 9.2R on a 1 TB HD.
>How-To-Repeat:
Go for example to this webpage, which doesn't use java/javascript, and click on the beamshot image:

http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html#Sheng-li_banklight-ld101

xorg is then going to 100% CPU use when clicking on it to get 100% view, for up to almost 2 minutes. Going back and clicking on the next beamshot image below it (also about 20 Mpixel) gives the same problem.
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: