Date: Wed, 6 Mar 2002 22:47:47 +0900 From: qhwt@myrealbox.com To: current@FreeBSD.ORG Subject: Re: Won't boot after the commits to timecounter code Message-ID: <20020306134746.GA342@gzl> In-Reply-To: <91591.1015400958@critter.freebsd.dk> References: <20020306054514.GA395@gzl> <91591.1015400958@critter.freebsd.dk>
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On Wed, Mar 06, 2002 at 08:49:18AM +0100, Poul-Henning Kamp wrote: > > In message <20020306054514.GA395@gzl>, qhwt@myrealbox.com writes: > > >Hello. > > >After upgrading to the kernel as of 2002-03-03 00:00:00(UTC), it stopped > > >booting just after the message: > > > > > >Timecounter "i8254" frequency 1193182 Hz > > > > > >With some debugging printf()'s inserted, I found it was tc->tc_get_timecount() > > >called from tco_delta() called just after the bcopy() in tc_windup(). > > >So maybe the next place I have to look at is i8254_get_timecount(), which is in > > >/sys/i386/isa/clock.c, but the last (effective) commit to this file is > > >revision 1.180(at the end of January). > > > > > >I couldn't even drop into DDB; no response other than to power button. > > >The last bootable(and stable so far) kernel is from 2002-02-24. > > >I don't think this is caused by some leftover in the work directory > > >since I always build kernels in a new empty directory under /usr/obj. > > > > > >Any (clue|fix)\? > > The only thing I know off right now is this thing from BDE which > I havn't been able to verify yet: > > > > ============================================================================ > From: Bruce Evans <bde@zeta.org.au> > Subject: dummy_timecounter broken; breaks booting with -d > To: <phk@freebsd.org> > Message-Id: <20020305075815.D2623-100000@gamplex.bde.org> > Date: Tue, 05 Mar 2002 08:09:26 +1100 > > %%% > Index: kern_tc.c > =================================================================== > RCS file: /home/ncvs/src/sys/kern/kern_tc.c,v > retrieving revision 1.116 > diff -u -2 -r1.116 kern_tc.c > --- kern_tc.c 26 Feb 2002 09:16:27 -0000 1.116 > +++ kern_tc.c 4 Mar 2002 21:08:03 -0000 > @@ -192,4 +252,14 @@ > gen = tc->tc_generation; > bintime2timeval(&tc->tc_offset, tvp); > + /* > + * XXX dummy_timecounter is now broken. Its tc_get_timecount > + * needs to be called before it works, and that doesn't > + * always happen naturally. In particular, we spin forever > + * here after booting with -d unless we do an unnatural call > + * here, since the screen timeout code is always run on entry > + * to ddb, and it calls here. > + */ > + if (gen == 0 && timecounter == &dummy_timecounter) > + (void)tc->tc_get_timecount(tc); > } while (gen == 0 || gen != tc->tc_generation); > } > %%% > > Bruce Hmm, this doesn't seem to change the situation. I tried reverting the following files: /sys/sys/timetc.h: 1.46 -> 1.45 /sys/kern/kern_tc.c: 1.116 -> 1.114 and managed to get into the single-user mode, but this of course doesn't solve the problem. I inserted a pair of printf() inside mtx_lock_spin/mtx_unlock_spin in i8254_get_timecount() and it kept printing the message while tc_init() was blocked, so I think it's blocked at mtx_lock_spin in i8254_get_timecount() when called from tc_init(), but not when called from somewhere else. (maybe an interrupt handler?) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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