new kernel for testing
Alan Cox
alan at redhat.com
Wed Jun 9 17:58:03 UTC 2004
On Wed, Jun 09, 2004 at 10:49:54AM -0700, Jesse Keating wrote:
> USB legacy keyboard/mouse stuff in the bios you mean? I'll certianly
> try that. I still don't understand why this would even come into play
> when pure ps/2 devices are used, or is that where the buggy bios comes
> into play?
Every access to the keyboard controller when USB legacy support is enabled
instead of accessing the hardware causes an SMM exception which then runs
a load of BIOS code which investigates both the real and USB devices and
fakes up a reply as if the device was PS/2. This allows things like DOS
to work with USB keyboards, its also an endless source of bugs because
SMM code is *hard* for even good BIOS people to get right.
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