Automatic driver reload with like with Microsoft Vista?

drag sidious linlamer at
Mon Dec 11 03:57:10 PST 2006

Now I've been a long time Linux user, of course, and haven't had a
chance to look at Microsoft Vista. However one of the long-touted
features for Vista is the new "VDDM" driver model with most of the video
driver moved out of the kernel.

Now I understand that this is how it's done in Linux for a while now,
correct? You have the DRM in-kernel, but as far as the DRI and EXA/XAA
stuff it's always been user-space. At least that is my limited

Well my question is this: 
In Vista there is a sort of watchdog or something that keeps track of
status of the GUI in some way. That is when the video driver goes
bonkers Vista has the ability swap out the driver for a different one
and then reload a new driver and recover from those sort of faults, is
this possible to do in

But I am very fuzzy on the details. I don't know if it kills the
applications running on that gui (I am assuming it doesn't), or if it
completely reboots the video card or whatnot. I don't know.

I had a interesting discussion on a online forum were a MS guy mentioned

"""The BSOD is still there. 

The black notes screen is the screen where everything goes black and
flips into text mode with ascii music notes displayed while a tone
sounds. It's the graphics driver being loaded and the graphics card
being initialized. Pulling this off outside of the boot process is
pretty impressive. """

and I was googling it for a while and I eventually tried Microsoft's
channel9 website and all I got was was this...
"""VDDM display drivers run in user mode in Vista. There is a kernel
mode miniport as well, but the main driver runs in user mode. Some of
the things they talked about RE: recovery from driver crashes applies
here. In Vista, if a display driver faults, Windows can reload the
driver or swap it with a different driver without having to reboot.
Driver upgrades can also be handled w/o a reboot. During the upgrade,
Windows unloads the current IHV driver, reverts to the standard VGA
driver, then loads in the new IHV driver."""

I expect that this would be a handy feature for end users. Since the
realities of video drivers mean that time to time hangs and such are
unavoidable I think that this feature would be handy.. Is there some
sort of heartbeat the system can do with the GUI to reset it if it
starts hanging? Is is possible to do this without loosing the user's

I am no developer, I am just curious.

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