> That helped a lot, the system seems to work normally now.
>
> Here's the relevant snippet from dmesg:
>
> [ 0.108006] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> [ 0.108006] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
> [ 0.108006] ...trying to set up timer (IRQ0) through the 8259A ... <3>
> [ 0.108006] ..... (found apic 0 pin 2) ...<3> failed.
> [ 0.108006] ...trying to set up timer as Virtual Wire IRQ...<3> works.
>
> and the whole thing is at: http://www.sisk.pl/kernel/debug/20080618/dmesg-2.log
Hmm, that only proved the 8259A is indeed wired to the pin #2 of the I/O
APIC.
> I, personally, don't have any and AMD only has SB600 documentation on its
> web page (it's still marked as "AMD confidential" ;-)).
Well, the IC block is most likely the same as that's not rocket science
and once done there is no need to fiddle with that. That written, I am
afraid there is nothing useful about the IC in the document, except that
it's there and consists of an I/O APIC providing 24 inputs and the usual
pair of 8259A cores. Thanks for the reference anyway.
> There is an interrupt controller in there, but I'm not sure if there's any
> 8259A. The northbridge is on the CPU, actually.
I will praise the day someone ships an x86 machine without an 8259A core!
As expressed in another mail I suspect there may actually be a direct
route from the 8254 to INTIN0 in the southbridge -- this is what other
bootstrap logs seen in the Internet suggest. This would mean this
particular BIOS is buggy (is it the latest version?) and provides an
incorrect IRQ override in its ACPI tables, for example because the
responsible block has been blindly copied from a machine using a commoner
wiring. This could be moderately easily fixed up with a quirk based on
the PCI ID (after checking it again, we actually used to have a quirk for
ATI in this area, but the way it was done suggests the issue was not
understood well enough).
Could you please remove the hack sent yesterday and test the patch
provided below? I do hope it builds, but I have no immediate means to
check it. Please report the output. The intent is to test INTIN0
directly before testing INTIN2 through the 8259A. Thanks.
Aside of that, what I have gathered from your reports (please correct me
if I have got it wrong) is that when the through-8259A mode is used, then
after a while 8254 timer interrupts stop arriving. What's interesting,
the "Virtual Wire IRQ" seems to work for you correctly (that's quite an
odd setup where a local APIC input is used in the native mode -- please
post /proc/interrupts for confirmation), which in turn implies the master
8259A drives its INT output as we expect. Why would the I/O APIC input
have problems then? Hmm...
[ mingo@elte.hu: revert the "x86: fix IO APIC breakage on HP nx6325"
version. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On Thu, 19 Jun 2008, Rafael J. Wysocki wrote:
> > With such a configuration the "x86: I/O APIC: timer through 8259A
> > second-chance" patch should not matter, because the only change it
> > introduces is an attempt to try the same I/O APIC pin again, but with the
> > IRQ0 line of the master 8259A enabled. That's not a terribly unusual
> > configuration and nothing should get confused in the system.
>
> But it _does_ get confused, really.
Something certainly gets confused, but so far I am not sure which bit
exactly it is, are you?
> > Barring the unlikely possibility of the 8259A actually being wired to
> > INTIN2 of the I/O APIC I can see two possible explanations:
> >
> > 1. The 8259A interrupt actually escapes to the CPU somehow and is handled
> > as an ExtINTA interrupt. This would make the code in check_timer()
> > decide it has found a working configuration, while actually it has been
> > fooled.
[...]
> Here you go:
>
> [ 0.108006] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> [ 0.108006] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
> [ 0.108006] ...trying to set up timer (IRQ0) through the 8259A ... <3>
> [ 0.108006] ..... (found apic 0 pin 2) ...<3> works.
>
> The full dmesg is at: http://www.sisk.pl/kernel/debug/20080618/dmesg-1.log
Thanks. In this case I suspect the case #1 quoted above happens, that is
the 8259A manages to deliver its interrupt somehow. Note at this stage it
is meant to be in the AEOI mode, so it can happily resubmit the interrupt
indefinitely with no additional handling as long as it receives INTA
cycles.
Can you please try the patch below on top of "x86: I/O APIC: timer
through 8259A second-chance" to see whether my hypothesis is true? It
modifies the through-8259A setup path so that the APIC input gets masked,
but the 8259A has the timer interrupt still enabled. Let me know how the
timer interrupt is routed in this case.
Bisected-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Each I/O APIC redirection table entry has a number of fields.
Define names for them to eliminate reference by hard coded
numbers.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If configured to use the I/O APIC, the NMI watchdog is deemed to fail if
the chip has been deactivated as a result of "noapic". Downgrade to the
local APIC watchdog similarly to what is done for the UP case.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If configured to use the I/O APIC, the NMI watchdog is deemed to fail if
the chip has been deactivated as a result of "nosmp". Downgrade to the
local APIC watchdog similarly to what is done for the UP case.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For the UP case the NMI watchdog downgrade is done consistently in
APIC_init_uniprocessor() now. Remove redundant code used only when
BIOS-disabled local APIC is activated.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If configured to use the I/O APIC, the NMI watchdog is deemed to fail if
the chip will not be used in the UP configuration, because "noapic" has
been specified or the chip is simply not there. Downgrade to the local
APIC watchdog to rectify.
The new #ifdef is ugly, I know. A proper solution is to provide suitable
definitions of smp_found_config, etc. for !CONFIG_X86_IO_APIC in a header.
Likewise the whole if () condition should be moved to a static inline
function. Such clean-ups are beyond the scope of this change and can be
done once the whole issue of the timer has been sorted out.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
A downgrade helper for the NMI watchdog to be used in all places where
the I/O APIC watchdog may have been requested, but the I/O APIC is found
not to be there or meant to be left disabled. This is so that the
reconfiguration is cosistent and defined in a single place only.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
nmi_watchdog=1 hangs on 64-bit:
[ 0.250000] Detected 12.564 MHz APIC timer.
[ 0.254178] APIC timer registered as dummy, due to nmi_watchdog=1!
[ 0.260366] Testing NMI watchdog ... <4>WARNING: CPU#0: NMI appears to be stuck (0->0)!
[ ... ]
[ 0.470003] calling genl_init+0x0/0xd0
[ hard hang ]
bisected it down to:
git-bisect start
git-bisect good 1beee8dc8c
git-bisect bad 11582ece0aaa2d0f94f345c08a4ab9997078a083
git-bisect bad 5479c623bb44089844022c03d4c0eb16d5b7a15f
git-bisect bad cfb4c7fabeb499e1c29f9d1878968e37a938e28a
git-bisect good 246dd412d3
git-bisect bad 3f8237eaff7dc1e35fa791dae095574fd974e671
git-bisect good 90e23b13ab849e2a11f00c655eb3a2011b4623be
git-bisect bad 833526a34eeefc117df3191a594c3c3a4f15a9ac
git-bisect good 791b93d3dfaf16c23e978bec0cc0a3dd9d855d63
git-bisect bad 65767c64068f2c93e56a1accfed5c78230ac12d7
git-bisect bad 2abc5c05dd82c188e3bdf6641a274f013348d14b
git-bisect bad 317e1f2597ffb4d4db940577bbe56dc6e881ef07
| 317e1f2597ffb4d4db940577bbe56dc6e881ef07 is first bad commit
| commit 317e1f2597ffb4d4db940577bbe56dc6e881ef07
| Author: Maciej W. Rozycki <macro@linux-mips.org>
| Date: Wed May 21 22:10:22 2008 +0100
| x86: I/O APIC: clean up the 8259A on a NMI watchdog failure
the problem is that in the dummy-lapic branch we rely on the i8259A
but if the NMI watchdog fails we turn off IRQ 0 - which doesnt work
too well ;-)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Not sure but maybe it is better to use NMI_DISABLED,
will take a look. But for now this patch is not change
anything in logic so it will not hurt/broke the kernel.
For most cases nmi_watchdog assignment is by one of NMI_*
macro so I think there it make sense too.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/io_apic_64.c: In function 'check_timer':
arch/x86/kernel/io_apic_64.c:1688: error: 'vector' undeclared (first use in this function)
arch/x86/kernel/io_apic_64.c:1688: error: (Each undeclared identifier is reported only once
arch/x86/kernel/io_apic_64.c:1688: error: for each function it appears in.)
Some systems incorrectly report the ExtINTA pin of the I/O APIC as the
genuine target of the timer interrupt. Here is a change that copies timer
pin information found to the other pin if one has been found only. This
way both a direct and a through-8259A route is tested with the pin letting
these problematic systems work well enough. If no timer pin information
has been found for the I/O APIC, then local APIC variations are tried
only, similarly to what is done without the change (except without the
misleading messages).
Obviously if we try the first-chance path without being told by the BIOS
to do so, we should not complain either, so do not print the message in
this case.
The 64-bit variation should be updated with a call to
replace_pin_at_irq() which can be done with the upcoming merge. Since
add_pin_to_irq() is now always called in the first-chance path, the
condition to require it in the second-chance path no longer happens.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Keep the timer interrupt line masked when reconfiguring its interrupt
redirection entry in the I/O APIC.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Unmask the timer interrupt line set up in the through-8259A mode
explicitly after setup_timer_IRQ0_pin() has set up the I/O APIC interrupt
redirection entry to let the two operations be unbound from each other.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Rename setup_ExtINT_IRQ0_pin() to setup_timer_IRQ0_pin() to better
reflect the upcoming role of a function setting up a (semi-)arbitrary I/O
APIC pin appropriately for the 8254 timer. By "appropriate" the following
settings are meant: edge-triggered, active-high, all the other settings
per-architecture. Adjust comments to reflect code appropriately. No
functional changes.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The LINT0 line of the local APIC is masked in the LVT0 entry in
check_timer() before this function is ever called. Removed the
redundant unmasking for better control.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Ingo Molnar
Christophe Jaillet
Maciej W. Rozycki
Paolo Ciarrocchi
Cyrill Gorcunov
Thomas Gleixner