>Number:         34986
>Category:       port-i386
>Synopsis:       Note that Dynamic Allocation of System RAM as VIdeo RAM must be disabled in system BIOS
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    port-i386-maintainer
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Nov 03 13:50:00 +0000 2006
>Originator:     Blair Sadewitz
>Release:        4.99.3
>Organization:
Organization?  Not much, I'm afraid.
>Environment:
NetBSD woody 4.99.3 NetBSD 4.99.3 (WOODY) #6: Wed Nov  1 02:57:59 EST 2006  blair@woody:/home/blair/cvs/src/sys/arch/amd64/compile/WOODY amd64

>Description:
Some [x86] systems have an integrated graphics controller which uses a variable amount of system RAM for its operations.  With driver support, this maximizes the amount of available RAM; without it, graphics operations become a critical reliability risk.  I use an intel D945Gtp motherboard with this graphics controller:

000:02:0: Intel 82945G/P Integrated Graphics Device (VGA display, revision 0x02)

If I do not disable ``DVMT'' in the BIOS, anything above a nominal load average will cause a hard lock within one hour--usually less.

This should perhaps be noted in the i386 and amd64 port FAQs, ``X11 on NetBSD'' FAQ, manpages, and other similar documentation.  Given the amount of systems out there which have Intel integrated graphics alone, it is critical that this be documented, otherwise potentially slews of [new] users will have the wrong impression regarding NetBSD's reliability and/or hardware support.

--Blair


>How-To-Repeat:
Document Intel DVMT technology, its implications upon system operation and reliability in those systems without appropriate drivers, and how to disable it in the BIOS.
>Fix:
Go into BIOS setup and select "Video Configuration" (I will get the name of the screen this is on if you wish).  Change the ``DVMT'' option to ``FIXED''.  On my system, even though I only allocate 128MB to Video RAM, the aperture must be set to 256MB or Xorg will hang the system.

I will write this documentation if desired.