/scrm/
On Fri, 23 Jul 1999, Maciej W. Rozycki wrote:
> On Wed, 21 Jul 1999, Sunshine wrote:
>
> > I am having some trouble getting any smp kernel to run on my ancient Pentium
> > system. The problem I am having is that ( from what I have read in various
> > linux smp documents) the my old Intel motherboard mp table is lying about
> > the IRQ for the Real Time Clock. Thus preventing me from booting. The
> > system boots up and detects both processors and then right after the IO-APIC
> > starts I get this:
> >
> > enabling symetric IO mode... done
> > ENABLING IO-APIC
> > ... No explicit IRQ entries, using default mptable.
> > changing APIC ID to 2 <-- I am not sure if I recalled this from memory
> > right
> > IO APIC pin 2, 13 not connected.
> > .. MP-BIOS bug: 8254 timer not connected to IO-APIC
> > ...trying to set up timer as ExtINT... failed
> ^^^^^^
> > ...tryng to set up timer as BP IRQ... failed
> > Kernel panic: IO APIC + timer doesn't work!
> > In swapper task - not syncing
> [...]
> > Linux version 2.2.5-15smp (root@porky.devel.redhat.com) (gcc version
> > egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)) #1 SMP Mon Apr 19 22:03:51
> > EDT 1999
> > Intel MultiProcessor Specification v1.1
> > Virtual Wire compatibility mode.
> ^^^^^^^^^^^^
> > I/O APIC at 0xFEC00000.
> > Bus #0 is EISA with no IRQ8 chaining
> > Processors: 2
> > mapped APIC to ffffe000 (fee00000)
> > mapped IOAPIC to ffffd000 (fec00000)
> > Detected 66664407 Hz processor.
> > Console: colour VGA+ 80x25
> > Calibrating delay loop... 26.52 BogoMIPS
> > Memory: 62752k/65536k available (1044k kernel code, 416k reserved, 968k
> > data, 68k init)
> > VFS: Diskquotas version dquot_6.4.0 initialized
> > Checking 386/387 coupling... Hmm, FPU using exception 16 error reporting
> > with FDIV bug.
> > Checking 'hlt' instruction... OK.
> > Intel Pentium with F0 0F bug - workaround enabled.
> > POSIX conformance testing by UNIFIX
> > per-CPU timeslice cutoff: 1.57 usecs.
> > CPU0: Intel Pentium 60/66 stepping 05
> > calibrating APIC timer ...
> > ..... CPU clock speed is 66.6638 MHz.
> > ..... system bus clock speed is 533.3073 MHz.
> ^^^^^^^^^^^^
> > Booting processor 1 eip 2000
> > Calibrating delay loop... 26.62 BogoMIPS
> > OK.
> > CPU1: Intel Pentium 60/66 stepping 05
> > Total of 2 processors activated (53.15 BogoMIPS).
>
> [I've marked log entries I am referring to below.]
>
> Have you noticed your local APIC timers get calibrated wrong? The value
> of 533.3073 MHz does not certainly match your bus clock, but if you divide
> it by 16 then you get the right value of 33 MHz (that's the speed of APIC
> bus, not the system one, BTW). As the APIC timer, once calibrated, is
> used as the reference clock, your system may miss the interrupt when
> performing 8254 setup.
>
> Actually, I cannot really imagine 8254 not working as ExtINT, as that's
> basically the way interrupts work when a system starts in the virtual wire
> compatibility mode (and your does).
>
> Basically current kernel versions do not handle 82489DX APICs at all
> (these are the separate chips used for pre-Pentium 75 setups which include
> i486 and Pentium60/66 boards). I sent an apropriate patch to set up
> 82489DXs correctly to linux-kernel a few weeks ago but (as usually)
> haven't got any feedback. I don't have such an old SMP system, so while I
> can assure it does not hurt systems with integrated local-APICs, I can't
> be sure it solves all problems with 82489DXs. I'm providing the patch
> again (see below).
>
> I would be pleased if you run it once, at least, and report me the
> results (a dmesg output would be appreciated). Note, the patch is against
> 2.3.10 but I tested it against 2.2.10 and it applied cleanly. You should
> have no problems with 2.2.5, too.
>
> Good luck!
>
> Maciej
>
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