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Differences between W2K and XP with "VGA MODE" boot option

VirtualLarry

VirtualLarry

No Lifer
Been doing some troubleshooting lately with a recent build, and some signs point to a potentially semi-fried video card, a 2MB PCI S3 Virge/DX board. It freezes variously at times, while running in normal boot mode, after installation. Install of both OSes (XP SP2 and W2K SP4) proceeded without incident.

In WinXP SP2:
Normal boot - freezes
VGA mode - freezes
safe mode - does not freeze

In W2K SP4:
Normal boot - freezes
VGA mode - does not freeze
safe mode - does not freeze


Some observations that explain the differences:
When booting W2K in VGA mode, visuals default to 640x480, 16-color mode (IOW, *real* "VGA mode"). Going to the Display properties and adjusting the resolution or color-depth sliders has no effect, and they default to the settings from normal boot mode. Applying modified settings doesn't change anything in the current OS session, although I suspect that future normal mode boots would use the new settings.

When booting XP in VGA mode, visuals default to 640x480, likewise, but adjusting the Display property settings and hitting "apply", IMMEDIATELY changes the settings. IMHO, this should not be so, if running truely in "VGA mode". XP really borked up something bigtime in how "VGA mode boot" operates.

The reason that this is such a PITA for me, is that I wanted this machine to be a secondary dev box, and I would use RDP to login to it. But due to something flaky with the video card, it freezes. If I could force XP to boot into VGA mode - properly - then it wouldn't be an issue. Booting XP into Safe Mode seems to disable so many background services, that it isn't a viable option. Worse yet, I can't manually overtop install a "Standard VGA" video adaptor over the auto-detected "S3 Virge DX/GX" out-of-box driver, at least I don't see how using the standard XP UI widgets. Choosing "Show all hardware" doesn't actually show everything like it used to in prior OS versions. I may have to homebrew a "Standard VGA" "have disk" .INF to feed it or something.

Something else semi-strange too - the resource allocation for my card shows A0000-AFFFF instead of A0000-BFFFF, which is what I thought was normal for a standard VGA-compatible adaptor?

So if there is any way to fix XP SP2's broken "VGA mode" boot, I would appreciate learning how, thanks.
 
Having had a recent bout of "boot to VGA" there is something I THINK I found from my readings at MS. If you use VGA mode in XP it will boot w/ the current video drivers set to VGA mode. So it would use the S3Virge driver but at low level. With NT (and I am presuming 2000 here but you should check) VGA mode boot using Windows native driver (vga.sys I believe) NOT the Virge driver. Thus the difference. In safe mode w/ XP also There it uses uses vga.sys not the Virge driver.
Sounds like a flaky Virge driver.
Addendum: XP and 2000 are behaving correctly. The screen difference is due to vga.sys using your set resolution in the registry. The other difference is due to using Virge driver but scaling back to a safe resolution. At least that's my observation after "poking around" in the registry.
 
Just get rid of all S3 Virge driver files (specially the OEM drivers included in XP: oem##.inf will have S3 driver info.). XP will have no clue what kind of video card is installed and it will force XP to start up w/ standard vga, not S3 drivers w/ safe settings.
 
In both cases, WinXP SP2 and W2K SP4, booting to "Safe Mode" seems to invoke the VGA.SYS MS default driver, but booting to "VGA mode" loads the actual card driver, but (in W2K's case), runs it only at a low level (VGA-compatible only), and keeps it locked there during the OS session. I verified this in the W2K case by using the "System Information" MMC snap-in, and checking the hardware resource usage listings. XP seems to start at a VGA-compatible resolution, but allows changes during that OS session, which to me seems fundementally flawed, when you consider what "VGA mode" boot is really for. (Hint: Think of true non-VGA-compatible graphics accelerator cards, ones requiring a seperate VGA core and BIOS to make them DOS compatible.)

Perhaps a better question in all of this is - can I run XP headless? Then again, I don't think that the mobo will even POST properly without some sort of video card installed.

Ok, found out I need to hack Display.inf and re-install. Blasted "ExcludeFromSelect=*" line is probably why I can't manually choose to install the VGA.SYS driver.

Edit: I hard-wired the Display.inf file for the Virge DX/GX to load the vga driver rather than s3m, seems to work ok thus far, no crashes. I can still RDP in to XP SP2, and get a 1024x768 / 16bpp display, so I'm happy. POST beeps strangely with no VGA monitor connected, but doesn't hang so I don't care.

Interesting bit of trivia I discovered - there is an upgrade database in the same .inf file, and guess which video card is specifically called out NOT to upgrade using the in-box drivers. Yup, you guessed it, out of all the cards and mfgs, the setup prefers to keep the older NT4.0 drivers instead of W2K or XP drivers for the Virge DX/GX. Now if any of the true gurus know the reasoning behind this - please, I'm all ears. Either MS knew that their in-box drivers were buggy on this particular hardware, or there are newer drivers released out there for NT4.0 and MS prefers you to use those.

What a stupid bloody hassle, for what should be one of the dumbest bog-standard PCI VGA boards out there. :|
 
Is it possible that the video card driver is at fault (i.e. not allowing XP to set the resolution to 640x480)?
 
OK Mr. smarty pants 🙂 Please tell me where to start to solve this problem
http://forums.anandtech.com/messageview...atid=34&threadid=1742661&enterthread=y
To sum it up I can only full boot with the /sos switch. Originally even safe mode wasn't an option but that oddly enough just went away and safe mode works as it should. Normal boot gives me the BSOD error code listed on the first post of the above thread. No "minidumps" since 4/05, long before this event. MS of course recommended a full format/reinstall or a parrallel install of XP home.
Other than the funny way of booting all seems to work just fine and stable. Computer runs 24/7 and no noticeable glitches at all. Seems like a waste to reformat/reinstall XP at this point.
 
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