[svlug] Wheel Mouse Optical... Evil?

Dagmar d'Surreal dagmar at dsurreal.org
Mon Jan 7 23:53:01 PST 2002


On Sat, 5 Jan 2002, Jeffrey Siegal wrote:

> Don't make assumptions just yet.  Just a few weeks ago, I saw a Logitech
> keyboard fail to work on Linux as well.  It had one of those USB-to-PS/2
> adapters that the WMO uses.  It wouldn't surprise me if that weren't
> part of the problem, and if this weren't MS deliberately sabotaging the
> mouse.
>
> I will be surprised if the Linux community doesn't figure this one out
> in short order.  Let's just wait a little while and see what happens
> before we start throwing out accusations about DMCA and so forth.

Well, I think that I finally figured out what was going on with my setup
(of course I spend months poking at it, and then six hours beating on it,
only to find out the actual cause 10 minutes after sending someone a damn
email about it) and it may be related to the problem you're seeing...

Check the BIOS on the motherboard for "USB Legacy Support".  On the ASUS
A7V at least it doesn't behave in as innocuous a fashion as would normally
be expected.  What it's SUPPOSED to do is if it sees a mouse on the USB
bus is silently translate what it sees there to emulate a PS/2 mouse
stuffed into the PS/2 port so operating systems like MS-DOS/PC-DOS that
don't have USB support (or for which it's a pain royale) can use the
hardware.  In reality it's trying to do this all the time, and basically
snatching resources from the actual PS/2 port... which breaks Linux's
drivers because they're not using ACPI routing to do that (and very
sensibly so).

I snuffed that option late last night and haven't had it screw up since.

On an amusing side note, while all my mice work flawlessly on both the USB
port and PS/2 ports in Linux now, Win98se still isn't working worth a damn
when the mouse is plugged into the USB port because Windows's
implementation of ACPI is assigning the blasted USB bridges to IRQ 10,
the same IRQ used by my GeForce2 GTS Pro.  Needless to say, performance
for both the mouse and video card goes straight to hell like this... so
I'm sticking with using the PS/2 port.  Wheeee.  (I put some hastily
written docs up last night linked from the top of www.dsurreal.org if
anyone wants my configuration info for the hardware.)

On a more functional side note, last night while reading the docs for the
nVidia kernel and GLX modules I noticed an option for GeForce2 or better
cards that enables a mouse shadow, ala WinXP.  Very cute.  :)






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