Problem with shutting down the Xserver

[Paul Goyette <paul%whooppee.com@localhost>]

Sometime not so long ago, my old video card died and I had to get a new 
one.  Ever since then, when I "log out" the Xserver locks up my system.

Details:

1. This has been happening at least since the end of May, running a
   -current 6.99.18 kernel.  I've just completed an update to
   yesterday's 6.99.22 and the problem still existgs.

2. I'm using "native" X from xsrc, _not_ using pkgsrc.

3. I use xdm to manage my one display.

4. The problem occurs whether I'm using my personal account (which has
   fvwm window manager) or root (which uses the default twm).  So it
   is unlikely to be related to the window manager.

5. When I terminate my X session, the screen resets and then goes
   completely black and a simple underline cursor appears at the
   top-left corner.  A few seconds later the cursor disappears.  As
   far as I can tell, the video card is still generating a valid
   signal, as the monitor does not display its "No signal" warning.

6. The video card being used is a nVidia GeForce GTX 1050 Ti:

   dmesg:
	vga0 at pci1 dev 0 function 0: vendor 10de product 1c82 (rev.
	0xa1)
	wsdisplay0 at vga0 kbdmux 1: console (80x25, vt100 emulation)

   lspci:
           +-03.0-[01]--+-00.0  NVIDIA Corporation GP107 [GeForce GTX 1050 Ti]
           |            \-00.1  NVIDIA Corporation GP107GL High Definition Audio Controller

   From the above you can see that I'm using the basic vga driver,
   since the nouveau driver doesn't handle such a modern card.

7. As far as I can tell, the X server is using the vesa display driver,
   with the vbe sub-module:

	...
	[   162.803] (II) LoadModule: "vesa"
	[   162.804] (II) Loading /usr/X11R7/lib/modules/drivers/vesa_drv.so
	[   162.815] (II) Module vesa: vendor="X.Org Foundation"
	[   162.815]    compiled for 1.18.4, module version = 2.4.0
	[   162.815]    Module class: X.Org Video Driver
	[   162.815]    ABI class: X.Org Video Driver, version 20.0
	...
	[   162.857] (II) VESA: driver for VESA chipsets: vesa
	[   162.857] (--) Using wscons driver on /dev/ttyE4 in pcvt compatibility mode (version 3.32)
	[   162.857] (--) using VT number 5
	[   162.886] (EE) [drm] Failed to open DRM device for pci:0001:01:00.0: -19
	[   162.890] (EE) [drm] Failed to open DRM device for pci:0001:01:00.0: -19
	[   162.890] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
	[   162.890] (II) Loading sub module "vbe"
	[   162.890] (II) LoadModule: "vbe"
	...
	[   163.001] (II) VESA(0): Creating default Display subsection in Screen section
	        "Builtin Default vesa Screen 0" for depth/fbbpp 24/32
	[   163.001] (==) VESA(0): Depth 24, (--) framebuffer bpp 32
	[   163.001] (==) VESA(0): RGB weight 888
	[   163.001] (==) VESA(0): Default visual is TrueColor
	[   163.001] (==) VESA(0): Using gamma correction (1.0, 1.0, 1.0)
	...

8. The problem occurs whether or not I execute a ``vesa on'' command
   in the boot loader.

9. The system doesn't reboot, and does not respond to network pings.
   It also does not seem to have entered DDB(4) since it appears to
   have (tried to) reset the video card and switch to vt0.  (I have
   ddb.onpanic set to "2" for some reason I cannot remember, and now
   I can't even find the docs on what "2" means!)


If I ``kill -KILL ...'' all of the processes related to xdm (including 
the X server itself), then the system does not hang, and I can log in on 
the console and manually execute ``/etc/rc.d/xdm start'' and everything 
is back to normal.  This would indicate to me that the X server is doing 
some sort of clean-up processing and that that is failing.

Has anyone else seen anything similar?  Any suggestions on how to debug 
this further?


+------------------+--------------------------+----------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:          |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee dot com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd dot org |
+------------------+--------------------------+----------------------------+