Distribution: Gentoo (Vanilla kernel though) 
Hardware Environment: 
# lspci 
0000:00:00.0 Host bridge: Intel Corp. 82845G/GL[Brookdale-G]/GE/PE DRAM 
Controller/Host-Hub Interface (rev 01) 
0000:00:01.0 PCI bridge: Intel Corp. 82845G/GL[Brookdale-G]/GE/PE Host-to-AGP 
Bridge (rev 01) 
0000:00:1d.0 USB Controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) 
USB UHCI Controller #1 (rev 01) 
0000:00:1d.1 USB Controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) 
USB UHCI Controller #2 (rev 01) 
0000:00:1d.2 USB Controller: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) 
USB UHCI Controller #3 (rev 01) 
0000:00:1d.7 USB Controller: Intel Corp. 82801DB/DBM (ICH4/ICH4-M) USB 2.0 
EHCI Controller (rev 01) 
0000:00:1e.0 PCI bridge: Intel Corp. 82801 PCI Bridge (rev 81) 
0000:00:1f.0 ISA bridge: Intel Corp. 82801DB/DBL (ICH4/ICH4-L) LPC Bridge (rev 
01) 
0000:00:1f.1 IDE interface: Intel Corp. 82801DB/DBL (ICH4/ICH4-L) UltraATA-100 
IDE Controller (rev 01) 
0000:00:1f.3 SMBus: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus 
Controller (rev 01) 
0000:00:1f.5 Multimedia audio controller: Intel Corp. 82801DB/DBL/DBM 
(ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01) 
0000:01:00.0 VGA compatible controller: nVidia Corporation NV25 [GeForce4 Ti 
4200] (rev a3) 
0000:02:08.0 Ethernet controller: Intel Corp. 82801BD PRO/100 VE (LOM) 
Ethernet Controller (rev 81) 
0000:02:09.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01) 
0000:02:0a.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
RTL-8139/8139C/8139C+ (rev 10) 
  
Software Environment: 
$ /usr/src/linux/scripts/ver_linux 
Linux cylob 2.6.7 #1 Sat Jun 26 00:07:26 CEST 2004 i686 Intel(R) Celeron(R) 
CPU 2.40GHz GenuineIntel GNU/Linux 
 
Gnu C                  3.3.3 
Gnu make               3.80 
binutils               2.14.90.0.8 
util-linux             2.12 
mount                  2.12 
module-init-tools      3.0 
e2fsprogs              1.34 
PPP                    2.4.1 
Linux C Library        2.3.3 
Dynamic linker (ldd)   2.3.3 
Procps                 3.1.15 
Net-tools              1.60 
Kbd                    1.12 
Sh-utils               5.2.0 
Modules Loaded         dvb_ttpci ttpci_eeprom saa7146_vv saa7146 stv0299 
dvb_core video_buf v4l2_common v4l1_compat videodev evdev usbmouse nvidia 
ppp_synctty ppp_async ppp_generic slhc smbfs eepro100 8139too snd_pcm_oss 
snd_mixer_oss snd_intel8x0 snd_ac97_codec snd_pcm snd_page_alloc gameport 
snd_mpu401_uart snd_rawmidi snd_seq_oss snd_seq_midi_event snd_seq snd_timer 
snd_seq_device snd usbcore sg sr_mod scsi_mod 
 
Problem Description: 
With enabled ACPI the system slows down to nearly nothing after one hour of 
system uptime. Pressing keys constantly remedies this for the time of pressing 
though (some works better than others, eg. num-/ works better than shift).. No 
clue why ;-)). 
 
The original patch for this was done for 2.6.5 and can be found here : 
http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-04/3174.html 
 
I worked the patch into my vanilla 2.6.7 source tree in 
arch/i386/kernel/io_apic.c and the slowdowns didn't stopped showing up since 
then (2 days and counting). Maybe it would be nice if someone checked it into 
the CVS tree (that is  if there aren't any specific reason not to). 
 
Steps to reproduce: 
Use a 2.6.x kernel on systems with TSC. 
Have fun seeing the slowdown to ZERO ;) after roughly one hour of waiting.