Re: Linux 2.6.17: PM-Timer bug warning?

[Con Kolivas <kernel@kolivas.org>]

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Chris Rankin writes:

> Hi,
> 
> I have found these messages in my dual P4 Xeon boot log:
> 
> Linux version 2.6.17 (chris@volcano.underworld) (gcc version 4.1.1 20060525 (Red Hat 4.1.1-1)) #2
> SMP PREEMPT Mon Jun 19 10:38:36 BST 2006
> BIOS-provided physical RAM map:
>  BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
>  BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
>  BIOS-e820: 0000000000100000 - 000000003ff75000 (usable)
>  BIOS-e820: 000000003ff75000 - 000000003ff77000 (ACPI NVS)
>  BIOS-e820: 000000003ff77000 - 000000003ff98000 (ACPI data)
>  BIOS-e820: 000000003ff98000 - 0000000040000000 (reserved)
>  BIOS-e820: 00000000fec00000 - 00000000fec90000 (reserved)
>  BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
>  BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
> 127MB HIGHMEM available.
> 896MB LOWMEM available.
> found SMP MP-table at 000fe710
> On node 0 totalpages: 262005
>   DMA zone: 4096 pages, LIFO batch:0
>   Normal zone: 225280 pages, LIFO batch:31
>   HighMem zone: 32629 pages, LIFO batch:7
> DMI 2.3 present.
> ACPI: RSDP (v000 DELL                                  ) @ 0x000febc0
> ACPI: RSDT (v001 DELL    WS 650  0x00000008 ASL  0x00000061) @ 0x000fd4d9
> ACPI: FADT (v001 DELL    WS 650  0x00000008 ASL  0x00000061) @ 0x000fd511
> ACPI: SSDT (v001   DELL    st_ex 0x00001000 MSFT 0x0100000d) @ 0xfffefa6f
> ACPI: MADT (v001 DELL    WS 650  0x00000008 ASL  0x00000061) @ 0x000fd585
> ACPI: BOOT (v001 DELL    WS 650  0x00000008 ASL  0x00000061) @ 0x000fd609
> ACPI: ASF! (v016 DELL    WS 650  0x00000008 ASL  0x00000061) @ 0x000fd631
> ACPI: DSDT (v001   DELL    dt_ex 0x00001000 MSFT 0x0100000d) @ 0x00000000
> ACPI: PM-Timer IO Port: 0x808
> 
> ...
> 
> Simple Boot Flag value 0x87 read from CMOS RAM was invalid
> Simple Boot Flag at 0x7a set to 0x1
> Machine check exception polling timer started.
> * This chipset may have PM-Timer Bug.  Due to workarounds for a bug,
> * this time source is slow. If you are sure your timer does not have
> * this bug, please use "pmtmr_good" to disable the workaround
> 
> It looks like my chipset is in the kernel's "gray-list" for having a hardware timer bug. So seeing
> as I *do* have the relevant hardware, what would I need do to determine whether this chipset
> actually does have the bug or not, please?
> 
> 00:00.0 Host bridge: Intel Corporation E7505 Memory Controller Hub (rev 03)
> 00:01.0 PCI bridge: Intel Corporation E7505/E7205 PCI-to-AGP Bridge (rev 03)
> 00:02.0 PCI bridge: Intel Corporation E7505 Hub Interface B PCI-to-PCI Bridge (rev 03)
> 00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller
> #1 (rev 01)
> 00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller
> #2 (rev 01)
> 00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller
> #3 (rev 01)
> 00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 01)
> 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 81)
> 00:1f.0 ISA bridge: Intel Corporation 82801DB/DBL (ICH4/ICH4-L) LPC Interface Bridge (rev 01)
> 00:1f.1 IDE interface: Intel Corporation 82801DB (ICH4) IDE Controller (rev 01)
> 00:1f.3 SMBus: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus Controller (rev 01)
> 00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97
> Audio Controller (rev 01)

We don't have such a list that tells us which hardware is prone otherwise we 
could have put the workaround for broken chipsets only. As your hardware is 
SMP then you'll have a good working TSC timer so I recommend simply removing 
the PM Timer option from your kernel configuration, or specify a different 
clocksource (TSC) in your bootparameters. I can't recall the syntax for it 
offhand.

--
-ck



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