2.4.1-ac$x and timer oddities

2.4.1-ac$x and timer oddities

[Richard A Nelson]

The machine boots and runs for some time without problems, but then
something makes the clock *very* jittery:

*  xscreensaver kicks in after almost no time (even betwixt quick
   keystrokes and in the middle of mouse movement), and the password prompt
   timer zips down to nothing post haste
*  neworking apps gets a time-out on almost all connections (netscape, ftp, etc)
*  It can take quite a while for focus to change after moving the mouse
*  The machine will hang (hard - CAD or SYSREQ B do nothing) after a
   variable amount of time (>8 hours)

I think this may've even started at 2.4.0, but seems to have gotten
worse recently.

Linux badlands.lexington.ibm.com 2.4.1-ac13 #7 Wed Feb 14 11:41:50 EST
2001 i686 unknown

Gnu C                  2.95.3
Gnu make               3.79.1
binutils               2.10.1.0.2
util-linux             2.10q
modutils               2.4.1
e2fsprogs              1.19
PPP                    2.4.0
Linux C Library        2.2.2
Dynamic linker (ldd)   2.2.2
Procps                 2.0.7
Net-tools              1.58
Console-tools          0.2.3
Sh-utils               2.0.11
Modules Loaded         nfs lockd sunrpc ipx af_packet netlink_dev
softdog olympic dummy0 usbcore maestro3 soundcore ac97_codec ipchains
eeprom sensors i2c-viapro i2c-core agpgart ipv6 unix

I have apm and acpi compiled in, but turned off:

Found and enabled local APIC!
mapped APIC to ffffe000 (fee00000)
Kernel command line: auto BOOT_IMAGE=Linux ro root=308 reboot=w apm=off acpi=off console=ttyS0,9600 console=tty0
CPU: Intel Pentium III (Katmai) stepping 03
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
enabled ExtINT on CPU#0
PCI: PCI BIOS revision 2.10 entry at 0xfd7ec, last bus=1
PCI: Using configuration type 1
PCI: Probing PCI hardware
Unknown bridge resource 0: assuming transparent
PCI: Using IRQ router VIA [1106/0596] at 00:02.0
Activating ISA DMA hang workarounds
apm: BIOS version 1.2 Flags 0x03 (Driver version 1.14)
apm: disabled on user request.
VP_IDE: IDE controller on PCI bus 00 dev 11
VP_IDE: chipset revision 6
VP_IDE: not 100% native mode: will probe irqs later
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
VP_IDE: VIA vt82c596b (rev 12) IDE UDMA66 controller on pci00:02.1
ACPI: Disabled

$ /lib/libc.so.6
GNU C Library stable release version 2.2.2, by Roland McGrath et al.
Copyright (C) 1992-1999, 2000, 2001 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 2.95.3 20010125 (prerelease).
Compiled on a Linux 2.4.2-pre2 system on 2001-02-12.
Available extensions:
        GNU libio by Per Bothner
        crypt add-on version 2.1 by Michael Glad and others
        linuxthreads-0.9 by Xavier Leroy
        BIND-8.2.3-T5B
        libthread_db work sponsored by Alpha Processor Inc
        NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
Report bugs using the `glibcbug' script to <bugs@gnu.org>.

XFree86 Version 4.0.2 / X Window System
(protocol Version 11, revision 0, vendor release 6400)
Release Date: 18 December 2000
-- 
Rick Nelson
Life'll kill ya                         -- Warren Zevon
Then you'll be dead                     -- Life'll kill ya

Re: 2.4.1-ac$x and timer oddities

[Ion Badulescu]

On Thu, 15 Feb 2001 15:57:09 -0500 (EST), Richard A Nelson <cowboy@vnet.ibm.com> wrote:
> The machine boots and runs for some time without problems, but then
> something makes the clock *very* jittery:
> 
> *  xscreensaver kicks in after almost no time (even betwixt quick
>    keystrokes and in the middle of mouse movement), and the password prompt
>    timer zips down to nothing post haste
> *  neworking apps gets a time-out on almost all connections (netscape, ftp, etc)
> *  It can take quite a while for focus to change after moving the mouse
> *  The machine will hang (hard - CAD or SYSREQ B do nothing) after a
>    variable amount of time (>8 hours)
> 
> I think this may've even started at 2.4.0, but seems to have gotten
> worse recently.

This patch (from Vojtech Pavlik) might help. Alan included it in 2.2.19pre,
so I'm not sure why he didn't add it to 2.4ac as well.

If it doesn't apply cleanly, do it by hand.

Hope this helps,
Ion

-- 
  It is better to keep your mouth shut and be thought a fool,
            than to open it and remove all doubt.
------------------------
--- linux-2.2.17/arch/i386/kernel/time.c.old	Sat Oct 28 00:04:09 2000
+++ linux-2.2.17/arch/i386/kernel/time.c	Sat Oct 28 00:02:10 2000
@@ -452,6 +452,14 @@
 		count = inb_p(0x40);    /* read the latched count */
 		count |= inb(0x40) << 8;
 
+		if (count > LATCH-1) {
+			outb_p(0x34, 0x43);
+		        outb_p(LATCH & 0xff, 0x40);
+			outb(LATCH >> 8, 0x40);
+			count = LATCH - 1;
+		}
+
+
 		count = ((LATCH-1) - count) * TICK_SIZE;
 		delay_at_last_interrupt = (count + LATCH/2) / LATCH;
 	}