port-amd64/49833: NetBSD-current (amd64/i386) reboot when start xinit on pc with HD6450

[kosaki_ka%ybb.ne.jpta@localhost]

>Number:         49833
>Category:       port-amd64
>Synopsis:       NetBSD-current (amd64/i386) reboot when start xinit on pc with HD6450
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Apr 10 02:45:00 +0000 2015
>Originator:     Kotaro Kosaki
>Release:        NetBSD 7.99.9 (GENERIC)
>Organization:
>Environment:
NetBSD phnm1 7.99.9 NetBSD 7.99.9 (GENERIC) #0: Thu Apr  9 17:29:30 JST 2015  kosaki@phnm1:/udd4/amd64/obj/sys/arch/amd64/compile/GENERIC amd64
>Description:
NetBSD-current (amd64/i386)  on pc with HD6450

console login ok
when  start xinit reboot
size of Xorg.0.log is 0

Mother board is
dual Opteron socket 940
Supermicro H8DCE-HTE (1234567890)
chipset nForce Pro 2200/2060
with onboard Rage XL vga

Graphics board is HD6450

may be a rare case?
>How-To-Repeat:
console login and start xinit

>Fix:
use previous version 

src/sys/external/bsd/drm2/dist/drm/radeon/radeon_agp.c ver 1.2
src/sys/external/bsd/drm2/dist/drm/radeon/radeon_object.c ver 1.2
src/sys/external/bsd/drm2/dist/drm/ttm/ttm_bo.c ver 1.6

This solves  reboot problem. But I think my case is rare,because no one report this reboot problem.