[ Normally I'd have replied to the original email but I couldn't figure out a way to subscribe to a list, and then reply to an email already posted to the list.] I have this very problem (with a different card): http://lists.freebsd.org/pipermail/freebsd-stable/2009-April/049618.html It looks like drm_open_helper() gets a NULL dev parameter and a panic occurs when it attempts to set dev->flags = flags. r189668, which was the MFC of r189052, seems to be the point where the problem showed up in the 7-STABLE branch. Regards, Navdeep ====================================================vgapci2@pci0:3:1:0: class=0x030000 card=0x02021787 chip=0x51591002 rev=0x00 hdr=0x00 vendor = 'ATI Technologies Inc' device = 'RV100 Radeon 7000 / Radeon VE' class = display subclass = VGA ====================================================Unread portion of the kernel message buffer: drm2: <ATI Radeon QY RV100 7000/VE> on vgapci2 device_attach: drm2 attach returned 2 Fatal trap 12: page fault while in kernel mode cpuid = 0; apic id = 00 fault virtual address = 0x3c fault code = supervisor write data, page not present instruction pointer = 0x8:0xffffffff80e28bfe stack pointer = 0x10:0xfffffffebe6f36a0 frame pointer = 0x10:0xfffffffebe6f36f0 code segment = base 0x0, limit 0xfffff, type 0x1b = DPL 0, pres 1, long 1, def32 0, gran 1 processor eflags = interrupt enabled, resume, IOPL = 3 current process = 1103 (Xorg) trap number = 12 panic: page fault cpuid = 0 Uptime: 30m9s Physical memory: 2033 MB Dumping 120 MB: 105 89 73 57 41 25 9 Reading symbols from /boot/kernel/drm.ko...Reading symbols from /boot/kernel/drm.ko.symbols...done. done. Loaded symbols for /boot/kernel/drm.ko Reading symbols from /boot/kernel/radeon.ko...Reading symbols from /boot/kernel/radeon.ko.symbols...done. done. Loaded symbols for /boot/kernel/radeon.ko #0 doadump () at pcpu.h:195 195 pcpu.h: No such file or directory. in pcpu.h (kgdb) where #0 doadump () at pcpu.h:195 #1 0x0000000000000004 in ?? () #2 0xffffffff8049a8b1 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:418 #3 0xffffffff8049acec in panic (fmt=0x104 <Address 0x104 out of bounds>) at /usr/src/sys/kern/kern_shutdown.c:574 #4 0xffffffff8075e70a in trap_fatal (frame=0xffffff0001c476e0, eva=Variable "eva" is not available. ) at /usr/src/sys/amd64/amd64/trap.c:764 #5 0xffffffff8075eab1 in trap_pfault (frame=0xfffffffebe6f35f0, usermode=0) at /usr/src/sys/amd64/amd64/trap.c:680 #6 0xffffffff8075f36f in trap (frame=0xfffffffebe6f35f0) at /usr/src/sys/amd64/amd64/trap.c:449 #7 0xffffffff807447ae in calltrap () at /usr/src/sys/amd64/amd64/exception.S:209 #8 0xffffffff80e28bfe in drm_open_helper (kdev=0xffffff0001bbb200, flags=3, fmt=Variable "fmt" is not available. ) at /usr/src/sys/modules/drm/drm/../../../dev/drm/drm_fops.c:50 #9 0xffffffff80e27510 in drm_open (kdev=0xffffff0001bbb200, flags=3, fmt=8192, p=0xffffff0001c476e0) at /usr/src/sys/modules/drm/drm/../../../dev/drm/drm_drv.c:597 #10 0xffffffff80464275 in giant_open (dev=0xffffff0001bbb200, oflags=3, devtype=8192, td=0xffffff0001c476e0) at /usr/src/sys/kern/kern_conf.c:342 #11 0xffffffff804341c7 in devfs_open (ap=0xfffffffebe6f38e0) at /usr/src/sys/fs/devfs/devfs_vnops.c:916 #12 0xffffffff8051f0ec in vn_open_cred (ndp=0xfffffffebe6f3a20, flagp=0xfffffffebe6f396c, cmode=Variable "cmode" is not available. ) at vnode_if.h:199 #13 0xffffffff8051ce23 in kern_open (td=0xffffff0001c476e0, path=0x7fffffffe850 <Address 0x7fffffffe850 out of bounds>, pathseg=Variable "pathseg" is not available. ) at /usr/src/sys/kern/vfs_syscalls.c:1042 #14 0xffffffff8075ed1c in syscall (frame=0xfffffffebe6f3c80) at /usr/src/sys/amd64/amd64/trap.c:907 #15 0xffffffff807449bb in Xfast_syscall () at /usr/src/sys/amd64/amd64/exception.S:330 #16 0x00000008019c8ffc in ?? () Previous frame inner to this frame (corrupt stack?)