amd64/161212: Radeon 4650 on amd64 crashes kernel on startx

[Patrick Mackinlay]

>Number:         161212
>Category:       amd64
>Synopsis:       Radeon 4650 on amd64 crashes kernel on startx
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Oct 01 17:20:03 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Patrick Mackinlay
>Release:        8.2-RELEASE
>Organization:
>Environment:
uname -a
FreeBSD patrick.uknet.spacesurfer.com 8.2-RELEASE FreeBSD 8.2-RELEASE #4: Sat Mar 12 18:34:49 GMT 2011     root at patrick.uknet.spacesurfer.com:/usr/obj/usr/src/sys/PATRICK  amd64

ATI Radeon HD 4650

xf86-video-ati-6.14.2
>Description:
I have an ATI Radeon HD 4650 on an amd64 machine. I am using xorg with xf86-video-ati-6.14.2. I have 2 monitors running at resolution 1920x1200.

When I run startx all works fine. However, if I exit my X session and run startx again then the kernel crashes and the system reboots.
>How-To-Repeat:

>Fix:


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