cvs commit: src/sys/bus/usb usb.c

Michael Neumann mneumann at
Tue May 27 05:14:59 PDT 2008

Matthew Dillon wrote:
:Isn't the BIOS on modern computers providing emulation of PS2 for USB
:keyboards? I have to organize a USB keyboard and try that out myself.
:If possible I'd like to have a clean solution. Right now, even delaying
:configuration until after interrupts are available seems to be a hack to
:me, at least doing it manually. Maybe something like NetBSD's autoconf
:framework would be a cleaner solution.
:   Michael
    Some BIOSes do do this, using SMM to emulate the PS2 port.  It has
    always been a bit hokey because the emulation doesn't always mesh
    properly when the kernel tries to switch over to the USB keyboard.
    Personally speaking I would rather not depend on such a feature.
I added a tunable "hw.usb.hack_defer_exploration" which reverts to the
old USB behaviour when set to 0 (defaults to 1).

It is considered a hack to not introduce any further regessions before
the 2.0 release. For the post 2.0 release, I am investigating in porting
the USB4BSD stack [1] to DragonFly which seems to be more mature, much
better documented and much cleaner (and MP safe). Depending on when the
2.0 will be see it's light, I could of course try to get it done for 2.0.



More information about the Commits mailing list