How to Use ddb(4)?
jhb at freebsd.org
Thu Jul 27 21:40:21 UTC 2006
On Thursday 27 July 2006 15:04, Hans Petter Selasky wrote:
> On Thursday 27 July 2006 20:40, Dag-Erling Smørgrav wrote:
> > maksim yevmenkin <maksim.yevmenkin at savvis.net> writes:
> > > Dag-Erling Smørgrav <des at des.no> writes:
> > > > No, kbdmux needs to be fixed so it works in DDB.
> > >
> > > actually, atkbd(4) needs to be fixed to support "polled" mode :)
> > It used to work fine before kbdmux(4) came along...
> Just a comment: Don't forget to lock Giant before calling anything in the
> keyboard layer. That means DDB must lock Giant, else at least my new USB
> keyboard driver will panic, saying Giant is not owned. The old USB keyboard
> driver did not care about this.
DDB should not be acquiring locks or depend on being able to do so. When you
panic the machine is an unknown state for one, and you really want to leave
the overall system state as undisturbed as possible while in the debugger to
aid in debugging.
More information about the freebsd-hackers