ICH3 - Pentium-M : Timer tick problems in IOAPIC mode

From: Francois Isabelle (isabellf_at_francoisisabelle.org)
Date: 05/31/04

  • Next message: Marcelo Tosatti: "Re: file attributes (ext2/3) in 2.4.26" 
    Date:	Mon, 31 May 2004 10:56:28 -0400
To: linux-kernel@vger.kernel.org

    Hi,
       I'm experiencing problems with the IOAPIC mode on a Pentium-M based
       board.

     Two symptoms show up:

      timer ticks stop after a little while, when this happens, activity on
      the serial console or local keyboard may unlock the timer tick and
      resume proper execution for a little while.

      timer ticks is unstable and accelerate, giving clock drift of 10% to
      500% depending on the board I/O load, especially serial and keyboard.

     Both the linux 2.4 and 2.6 series show this problem.
     Linux 2.4.22 (vanilla with SMP) see attachement
     Linux 2.6.5 (with SMP) see attachement

     Hardware Summary:
             Intel Pentium M,
            Intel 7501 ,
            Intel ICH3
            Winbond 83627HF
     
     My understanding is that ICH3 chip integrates both the APIC and the
     timer, I noted that even in IOAPIC mode linux acknowledges the IRQ0 to
     the 8259 PIC, it seems possible that the linux code masks IRQ0 and
     doesn't unmask it but I couldn't find the location.
     
     This problem is more likely to show up when the "BIOS Legacy USB"
     support is enabled, this is an SMI source.
     
     This problem never showed up in XT-PIC interrupt mode.

     If anyone experienced a similar problem, I'll be very glad to hear
     about it, as well as a possible fix or workaround. (other than disable
     apic).

     Thank you.
     Francois Isabelle
     isabellf@sympatico.ca

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  • Next message: Marcelo Tosatti: "Re: file attributes (ext2/3) in 2.4.26"