Bug#503029: False joystick events while high cpu load

[Radek <radoslaww@gmail.com>]

Package: linux-image-2.6.26-1-amd64
Version: 2.6.26-8
Severity: important

*** Please type your report below this line ***

While high cpu load there are false joystick input events like moving
joystick to it's down-right position. Here is how to reproduce:

1. run:

	jstest /dev/input/js0

you see it's output like this:

Axes:  0:     0  1:     0 Buttons:  0:off  1:off  2:off  3:off  4:off
5:off

2. in another terminal run something that increses your cpu load, for
example:

	while true; do true; done

(if you run graphical session you can just also try to move your window
fast left and right to increase cpu load, instead).

3. Look at the output of jstest, you see:

Axes:  0: 32767  1: 32767 Buttons:  0:off  1:off  2:off  3:off  4:off
5:off

When you break above intensive loop (or stop moving window), jstest output
is normal again.

The effect of this issue is you are unable to use joystick in most
games, of course. The same issue is on current Ubuntu 8.04 amd64
distibution.

Joystick related modules used: emu10k1_gp, analog (with map=gamepad
option).

Radek Warowny

-- Package-specific info:
** Version:
Linux version 2.6.26-1-amd64 (Debian 2.6.26-8) (waldi@debian.org) (gcc
version 4.1.3 20080623 (prerelease) (Debian 4.1.2-23)) #1 SMP Thu Oct
9 14:16:53 UTC 2008

** Command line:
root=/dev/mapper/vg1-lvroot ro rootflags=data=writeback

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.26-1-amd64 (SMP w/1 CPU core)
Locale: LANG=pl_PL.UTF-8, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages linux-image-2.6.26-1-amd64 depends on:
ii  debconf [debconf-2.0]         1.5.22     Debian configuration management sy
ii  initramfs-tools [linux-initra 0.92j      tools for generating an initramfs
ii  module-init-tools             3.4-1      tools for managing Linux kernel mo

linux-image-2.6.26-1-amd64 recommends no packages.

Versions of packages linux-image-2.6.26-1-amd64 suggests:
ii  grub                          0.97-47    GRand Unified Bootloader (Legacy v
pn  linux-doc-2.6.26              <none>     (no description available)