kern/40029: PCI Matrox G450 vs. mgadrm(4) -> panic

[svs%ropnet.ru@localhost]

>Number:         40029
>Category:       kern
>Synopsis:       PCI Matrox G450 vs. mgadrm(4) -> panic
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Nov 25 22:20:00 +0000 2008
>Originator:     Sergey Svishchev
>Release:        amd64 5.99.02
>Organization:
>Environment:
>Description:
As stated in sys/dev/pci/drm/mga_drv.c, PCI G450's are not supported by the 
driver:

mgadrm0 at vga0: Matrox G400/G450 (AGP) (unit 0)
error: [drm:pid0:drm_load] *ERROR* Card isn't AGP, or couldn't initialize AGP.

Still, running 'sysctl hw.dri' on such machine should not lead to panic:

uvm_fault(0xffff80004740a2e8, 0x0, 1) -> e
fatal page fault in supervisor mode
trap type 6 ...
kernel: page fault trap, code=0

trace:

turnstile_block()
mutex_vector_enter()
drm_name_info() at netbsd:drm_name_info+0xe3
sysctl_dispatch()
sys___sysctl()
syscall()

drm_name_info+0xe3 is line 145 in sys/dev/drm/drm_sysctl.c rev 1.3:

        if (dev->unique) {
                snprintf(buf, sizeof(buf), " %s", dev->unique);
                hasunique = 1;
        }

>How-To-Repeat:

>Fix: