Impact: find right nr_irqs_gsi on some systems.
One test-system has gap between gsi's:
[ 0.000000] ACPI: IOAPIC (id[0x04] address[0xfec00000] gsi_base[0])
[ 0.000000] IOAPIC[0]: apic_id 4, version 0, address 0xfec00000, GSI 0-23
[ 0.000000] ACPI: IOAPIC (id[0x05] address[0xfeafd000] gsi_base[48])
[ 0.000000] IOAPIC[1]: apic_id 5, version 0, address 0xfeafd000, GSI 48-54
[ 0.000000] ACPI: IOAPIC (id[0x06] address[0xfeafc000] gsi_base[56])
[ 0.000000] IOAPIC[2]: apic_id 6, version 0, address 0xfeafc000, GSI 56-62
...
[ 0.000000] nr_irqs_gsi: 38
So nr_irqs_gsi is not right. some irq for MSI will overwrite with io_apic.
need to get that with acpi_probe_gsi when acpi io_apic is used
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On some boxes there exist both RSDT and XSDT table. But unfortunately
sometimes there exists the following error when XSDT table is used:
a. 32/64X address mismatch
b. The 32/64X FACS address mismatch
In such case the boot option of "acpi=rsdt" is provided so that
RSDT is tried instead of XSDT table when the system can't work well.
http://bugzilla.kernel.org/show_bug.cgi?id=8246
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
cc:Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Impact: reduce stack size, use new API.
Replace cpumask_t with cpumask_var_t.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Reduce future system panics due to cpumask operations using NR_CPUS
Insure that code does not look at bits >= nr_cpu_ids as when cpumasks are
allocated based on nr_cpu_ids, these extra bits will not be defined.
Also some other minor updates:
* change in to use cpu accessor function set_cpu_present() instead of
directly accessing cpu_present_map w/cpu_clear() [arch/x86/kernel/reboot.c]
* use cpumask_of() instead of &cpumask_of_cpu() [arch/x86/kernel/reboot.c]
* optimize some cpu_mask_to_apicid_and functions.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When ACPI is asked to find an MADT (APIC table)
and fails, then ACPI expects to run in PIC mode.
However, if an MP Table is was found, IRQs will be
registered as if an IOAPIC is being used, even
though ACPI is configuring interrupt links links for PIC mode.
In this scenario, disable MPS so that IRQs
are registered in PIC mode, consistent with ACPI.
http://bugzilla.kernel.org/show_bug.cgi?id=12257
Signed-off-by: Len Brown <len.brown@intel.com>
Impact: cleanup
reorder exit path in __get_smp_config().
also move two print outs to acpi_process_madt
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This removes the acpi_irq_balance_set() interface from the PCI
interrupt link driver.
x86 used acpi_irq_balance_set() to tell the PCI interrupt link
driver to configure links to minimize IRQ sharing. But the link
driver can easily figure out whether to turn on IRQ balancing
based on the IRQ model (PIC/IOAPIC/etc), so we can get rid of
that external interface.
It's better for the driver to figure this out at init-time. If
we set it externally via the x86 code, the interface reduces
modularity, and we depend on the fact that acpi_process_madt()
happens before we process the kernel command line.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: fix section mismatch warning - apic_x2apic_phys
x86: fix section mismatch warning - apic_x2apic_cluster
x86: fix section mismatch warning - apic_x2apic_uv_x
x86: fix section mismatch warning - apic_physflat
x86: fix section mismatch warning - apic_flat
x86: memtest fix use of reserve_early()
x86 syscall.h: fix argument order
x86/tlb_uv: remove strange mc146818rtc include
x86: remove redundant KERN_DEBUG on pr_debug
x86: do_boot_cpu - check if we have ESR register
x86: MAINTAINERS change for AMD microcode patch loader
x86/proc: fix /proc/cpuinfo cpu offline bug
x86: call dmi-quirks for HP Laptops after early-quirks are executed
x86, kexec: fix hang on i386 when panic occurs while console_sem is held
MCE: Don't run 32bit machine checks with interrupts on
x86: SB600: skip IRQ0 override if it is not routed to INT2 of IOAPIC
x86: make variables static
Impact: make warning message disappear - functionality unchanged
Problems with bogus IRQ0 override of those laptops should be fixed
with commits
x86: SB600: skip IRQ0 override if it is not routed to INT2 of IOAPIC
x86: SB450: skip IRQ0 override if it is not routed to INT2 of IOAPIC
that introduce early-quirks based on chipset configuration.
For further information, see
http://bugzilla.kernel.org/show_bug.cgi?id=11516
Instead of removing the related dmi-quirks completely we'd like to
keep them for (at least) one kernel version -- to double-check whether
the early-quirks really took effect. But the dmi-quirks need to be
called after early-quirks are executed. With this patch calling
sequence for dmi-quriks is changed as follows:
acpi_boot_table_init() (dmi-quirks)
...
early_quirks() (detect bogus IRQ0 override)
...
acpi_boot_init() (late dmi-quirks and setup IO APIC)
Note: Plan is to remove the "late dmi-quirks" with next kernel version.
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
for !CONFIG_HAVE_SPARSE_IRQ
fix:
In file included from arch/x86/kernel/early-quirks.c:18:
include/asm/io_apic.h: In function 'probe_nr_irqs':
include/asm/io_apic.h:209: error: 'NR_IRQS' undeclared (first use in this function)
include/asm/io_apic.h:209: error: (Each undeclared identifier is reported only once
include/asm/io_apic.h:209: error: for each function it appears in.)
v2: fix by Ingo
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Until now, NR_IRQS was derived from black magic defines that had to
be "large enough" to both accomodate NR_CPUS and MAX_NR_IO_APICs.
This resulted in a way too large irq_desc[] array on most x86 systems.
Especially with larger CPU masks, the size of irq_desc can spiral out
of control quickly.
So be smarter about it and use precise allocation instead: determine the
default maximum possible IRQ number from the ACPI MADT. Use a minimum limit
of at least 32 IRQs for broken BIOSes.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/acpi/boot.c💯 warning: 'acpi_mcfg_64bit_base_addr' defined
but not used
http://bugzilla.kernel.org/show_bug.cgi?id=11743
Signed-off-by: Pavel Vasilyev <linuxoid@tochka.ru>
Signed-off-by: Len Brown <len.brown@intel.com>
This merges phase 1 of the x86 tree, which is a collection of branches:
x86/alternatives, x86/cleanups, x86/commandline, x86/crashdump,
x86/debug, x86/defconfig, x86/doc, x86/exports, x86/fpu, x86/gart,
x86/idle, x86/mm, x86/mtrr, x86/nmi-watchdog, x86/oprofile,
x86/paravirt, x86/reboot, x86/sparse-fixes, x86/tsc, x86/urgent and
x86/vmalloc
and as Ingo says: "these are the easiest, purely independent x86 topics
with no conflicts, in one nice Octopus merge".
* 'x86-v28-for-linus-phase1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (147 commits)
x86: mtrr_cleanup: treat WRPROT as UNCACHEABLE
x86: mtrr_cleanup: first 1M may be covered in var mtrrs
x86: mtrr_cleanup: print out correct type v2
x86: trivial printk fix in efi.c
x86, debug: mtrr_cleanup print out var mtrr before change it
x86: mtrr_cleanup try gran_size to less than 1M, v3
x86: mtrr_cleanup try gran_size to less than 1M, cleanup
x86: change MTRR_SANITIZER to def_bool y
x86, debug printouts: IOMMU setup failures should not be KERN_ERR
x86: export set_memory_ro and set_memory_rw
x86: mtrr_cleanup try gran_size to less than 1M
x86: mtrr_cleanup prepare to make gran_size to less 1M
x86: mtrr_cleanup safe to get more spare regs now
x86_64: be less annoying on boot, v2
x86: mtrr_cleanup hole size should be less than half of chunk_size, v2
x86: add mtrr_cleanup_debug command line
x86: mtrr_cleanup optimization, v2
x86: don't need to go to chunksize to 4G
x86_64: be less annoying on boot
x86, olpc: fix endian bug in openfirmware workaround
...
This PCI ID based quick should be a full solution for the IRQ0 override
related slowdown problem on SB450 based systems:
33fb0e4: x86: SB450: skip IRQ0 override if it is not routed to INT2 of IOAPIC
Emit a warning in those cases where the DMI quirk triggers but
the PCI ID based quirk didnt.
If this warning does not trigger then we can phase out the DMI quirks.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is a bug in the BIOSes of some HP boxes with AMD Turions which
connects IO-APIC pins with ACPI thermal trip points in such a way that
if the state of the IO-APIC is not as expected by the (buggy) BIOS, the
thermal trip points are set to insanely low values (usually all of them
become 16 degrees Celsius). As a result, thermal throttling kicks in
and knock the system down to its shoes.
Unfortunately some of the recent IO-APIC changes made the bug show up.
To prevent this from happening, blacklist machines that are known to be
affected (nx6115 and 6715b in this particular case).
This fixes http://bugzilla.kernel.org/show_bug.cgi?id=11516 listed as
a regression from 2.6.26.
On my box it was caused by:
commit 691874fa96
Author: Maciej W. Rozycki <macro@linux-mips.org>
Date: Tue May 27 21:19:51 2008 +0100
x86: I/O APIC: timer through 8259A second-chance
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
and the whole story is described in this (huge) thread:
http://marc.info/?l=linux-kernel&m=121358440508410&w=4
Matthew Garrett told us about that happening on the nx6125:
http://marc.info/?l=linux-kernel&m=121396307411930&w=4
and then Maciej analysed the breakage on the basis of a DSDT from the
nx6325:
http://marc.info/?l=linux-kernel&m=121401068718826&w=4
As far as the Dmitry's and Jason's boxes are concerned, I recognized the
symptoms and asked them to verify that the blacklisting helped.
It appears that the buggy BIOS code has been copy-pasted to the entire
range of machines, for no good reason.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Jason Vas Dias <jason.vas.dias@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
acpi_mcfg_64bit_base_addr is used when CONFIG_PCI_MMCONFIG is enabled.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
after following patch,
commit 1b313f4a6d
Author: Cyrill Gorcunov <gorcunov@gmail.com>
Date: Mon Aug 18 20:45:57 2008 +0400
x86: apic - generic_processor_info
- use physid_set instead of phys_cpu and physids_or
- set phys_cpu_present_map bit AFTER check for allowed
number of processors
- add checking for APIC valid version in 64bit mode
(mostly not needed but added for merging purpose)
- add apic_version definition for 64bit mode which
is used now
we are getting warning for acpi path on 64 bit system.
make the 64-bit side fill in apic_version[] as well.
[ mingo@elte.hu: build fix ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
SGI UV will have MMCFG base addresses that are greater than 4GB (32 bits).
v2: Use CONFIG_RESOURCES_64BIT instead of CONFIG_X86_64.
v3: Create a flag, that is set by platform specific code,
to disable the > 4GB check.
Signed-off-by: John Keller <jpk@sgi.com>
Cc: jpk@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There are a couple of places where (P)Dprintk is used which is an old
compile time enabled printk wrapper. Convert it to the generic
pr_debug().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Now that IRQ2 is never made available to the I/O APIC, there is no need
to special-case it and mask as a workaround for broken systems. Actually,
because of the former, mask_IO_APIC_irq(2) is a no-op already.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
also remove GET_APIC_ID when read_apic_id is used.
need to apply after
[PATCH] x86: mach_apicdef.h need to include before smp.h
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
x2apic support. Interrupt-remapping must be enabled before enabling x2apic,
this is needed to ensure that IO interrupts continue to work properly after the
cpu mode is changed to x2apic(which uses 32bit extended physical/cluster
apic id).
On systems where apicid's are > 255, BIOS can handover the control to OS in
x2apic mode. Or if the OS handover was in legacy xapic mode, check
if it is capable of x2apic mode. And if we succeed in enabling
Interrupt-remapping, then we can enable x2apic mode in the CPU.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have two conflicting DMA-based quirks in there for the same set of
boxes (HP nx6325 and nx6125) and one of them actually breaks my box.
So remove the extra code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: =?iso-8859-1?q?T=F6r=F6k_Edwin?= <edwintorok@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
when more than 4g memory is installed, don't map the big hole below 4g.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
and let 64-bit to fall back to use fixmap too.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix:
arch/x86/kernel/acpi/boot.c: In function ‘dmi_ignore_irq0_timer_override’:
arch/x86/kernel/acpi/boot.c:1443: error: implicit declaration of function ‘force_mask_ioapic_irq_2’
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The problems are that, with the ACPI vs timer overring issue _fixed_,
after using the box for some time (between several seconds and 1 hour, at
random) processes get very high CPU loads (once I've got X using 107% of
the CPU, for example) and the system becomes unresponsive, as though there
were interrupts lost or something similar.
Andreas Herrman reproduced similar problems:
> Ok, now I've reproduced the stability problem.
> - Using tip/master,
> - reverting e38502eb8aa82314d5ab0eba45f50e6790dadd88 and
> - applying your patch from this posting
> http://marc.info/?l=linux-kernel&m=121539354224562&w=4
>
> Starting X, firefox, gimp, tuxpaint and doing some drawing in tuxpaint
> results in a slow system. Drawing is almost not possible anymore --
> Selections of new colors, cursors etc. is performed with huge delay
> if it's performed at all.
>
> BTW, the code sets up timer IRQ as Virtual Wire IRQ:
>
> Jul 8 14:57:58 kodscha IO-APIC (apicid-pin) 2-22, 2-23 not connected.
> Jul 8 14:57:58 kodscha ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
> Jul 8 14:57:58 kodscha ...trying to set up timer as Virtual Wire IRQ... works.
>
> and both INT0 and INT2 of IOAPIC are masked:
>
> Jul 8 14:57:58 kodscha NR Dst Mask Trig IRR Pol Stat Dmod Deli Vect:
> Jul 8 14:57:58 kodscha 00 000 1 0 0 0 0 0 0 00
> Jul 8 14:57:58 kodscha 01 003 0 0 0 0 0 1 1 31
> Jul 8 14:57:58 kodscha 02 003 1 0 0 0 0 0 0 30
>
> I've also seen strange CPU utilization -- with syslog-ng:
>
> top - 15:33:06 up 35 min, 4 users, load average: 1.70, 0.68, 0.37
> Tasks: 64 total, 4 running, 60 sleeping, 0 stopped, 0 zombie
> Cpu0 : 0.0%us,100.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
> Cpu1 : 6.4%us, 87.2%sy, 0.0%ni, 5.8%id, 0.0%wa, 0.6%hi, 0.0%si, 0.0%st
> Mem: 895384k total, 283568k used, 611816k free, 35492k buffers
> Swap: 1959920k total, 0k used, 1959920k free, 163044k cached
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 4632 root 20 0 17216 800 580 S 104 0.1 0:34.22 syslog-ng
> 28505 root 20 0 205m 11m 4024 S 6 1.3 0:21.16 X
> 28518 root 20 0 56292 5652 4492 S 1 0.6 0:01.80 fluxbox
> 1 root 20 0 3724 608 508 S 0 0.1 0:00.36 init
>
> So far I have no clue why C1E-idle in conjunction with virtual wire
> mode causes this strange behaviour.
>
> ... and I start to think about the root cause of all this.
>
> I've performed similar tests under X with the IRQ0/INT0 configuration and
> I did not see above symptoms.
So lets fall back to the IRQ0/INT0 configuration on this box.
This basically restores the dont-use-the-lapic-timer exception mechanism
that was unconditional on this box prior commit 8750bf5 ("x86: add C1E
aware idle function").
Signed-off-by: Ingo Molnar <mingo@elte.hu>
if acpi=off, acpi=noirq and pci=noacpi, we need to disable apic.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Some HP laptops have a problem with their DSDT reporting as
HP/SB400/10000, which includes some code which overrides all temperature
trip points to 16C if the INTIN2 input of the I/O APIC is enabled. This
input is incorrectly designated the ISA IRQ 0 via an interrupt source
override even though it is wired to the output of the master 8259A and
INTIN0 is not connected at all. So far two models have been identified,
namely nx6125 and nx6325.
Use a knob provided by the I/O APIC interrupt registration code to
abandon any attempts to route IRQ 0 through the I/O APIC for these
systems.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
As discovered recently some systems exhibit problems when the 8254 timer
IRQ is routed through the I/O APIC. These problems do not affect the
timer IRQ itself and therefore cannot be detected when the correctness of
operation of the interrupt is verified in check_timer(). Therefore the
I/O APIC path of the timer IRQ has to be disabled entirely.
This is a change that lets platforms ask for the timer IRQ not to be
registered in the I/O APIC interrupt tables. The local APIC and ExtINTA
paths are unaffected. This request is only taken into account for ACPI
platforms as MP table systems seem unaffected so far.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
if the system doesn't have ioapic, we don't need to store entries for mptable
update
also let mp_config_acpi_gsi not call func in mpparse
so later could decouple mpparse with acpi more easily
Reported-by: Daniel Exner <dex@dragonslave.de>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daniel Exner <dex@dragonslave.de>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
so we don't get the same value multiple times.
also make mp_config_acpi_legacy_irqs more readable by moving assignments
together.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Daniel Exner reported IO-APIC enumeration breakage in linux-next.
Alexey Starikovskiy found out that it might be related to
commit 2944e16b25 "x86: update mptable".
use enable_update_mptable to decide if need check before add mp_irqs array.
Reported-by: Daniel Exner <webmaster@dragonslave.de>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
... so it could fall back to normal numa and we'd reduce the impact of the
NUMAQ subarch.
NUMAQ depends on GENERICARCH
also decouple genericarch numa from acpi.
also make it fall back to bigsmp if apicid > 8.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
for http://bugzilla.kernel.org/show_bug.cgi?id=10613
BIOS bug, APIC version is 0 for CPU#0! fixing up to 0x10. (tell your hw vendor)
v2: fix 64 bit compilation
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Gabriel C <nix.or.die@googlemail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
make mptable to be consistent with acpi routing, so we could:
1. kexec kernel with acpi=off
2. work around BIOSes where acpi routing is working, but mptable is
not right, so can use kernel/kexec to start other OSes that don't have
good acpi support.
command line: update_mptable
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
