Date: Mon, 28 Nov 2005 17:04:57 -0500 From: John Baldwin <jhb@freebsd.org> To: Scott Long <scottl@samsco.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/amd64/amd64 machdep.c Message-ID: <200511281704.59091.jhb@freebsd.org> In-Reply-To: <438B7BFC.7030604@samsco.org> References: <200511211839.jALIdIff064683@repoman.freebsd.org> <200511281637.11153.jhb@freebsd.org> <438B7BFC.7030604@samsco.org>
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On Monday 28 November 2005 04:51 pm, Scott Long wrote: > John Baldwin wrote: > > On Monday 28 November 2005 04:06 pm, Scott Long wrote: > >>John Baldwin wrote: > >>>On Monday 21 November 2005 01:39 pm, John Baldwin wrote: > >>>>jhb 2005-11-21 18:39:17 UTC > >>>> > >>>> FreeBSD src repository > >>>> > >>>> Modified files: > >>>> sys/amd64/amd64 machdep.c > >>>> Log: > >>>> Expand the hack to mask the atpics if 'device atpic' is not in the > >>>>kernel during boot up. Now we do a full reset of the 8259As and setup > >>>> a simple interrupt handler (we actually borrow the apic one that just > >>>> does an immediate iret) to handle any spurious interrupts triggered by > >>>> either chip. This should fix some folks that were getting a Trap 30 > >>>> during bootup of certain SMP AMD systems. This might get pushed into > >>>> the 6.0 branch as an errata. For now a suitable workaround is to add > >>>> 'device atpic' to your kernel config. > >>>> > >>>> Tested by: scottl > >>>> Helpful info from: dillon > >>>> MFC after: 1 week > >>> > >>>Hmm, we probably still need to reprogram the ATPIC on resume as well. > >>>I'm not sure it's actually worth not just compiling the atpic code in on > >>>amd64. > >> > >>Problems aside, what are the benefits to not having the atpic > >>unconditionally included on amd64? > > > > Purely space savings. It's whatever the size of atpic.o, elcr.o, and the > > bits of atpic_vector.S that make it into exception.o are. > > Ok, so it doesn't cut down on runtime overhead? The file sizes look to > be: > > atpic.o 15k > elcr.o 2.5k > exception.o 200byte delta No, there isn't any effect on runtime. > If, down the road, a motherboard shows up without an atpic or one that > is horribly broken, would we be worse off for having the atpic code in > there? Well, both i386 and amd64 assume an atpic is there. Even if you don't include 'device atpic' on amd64, we do the manual bit banging to the I/O ports that assume it is there in the code I just changed. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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