A couple of months ago I noticed that a number of computationally expensive programs (like geoprocessing 100's of millions of points, and running computational fluid dynamics simulations) started returning nan's occasionally. These same application run on the beowulf cluster, other laptops running Gentoo, and a Win-XP machine. I have *finially* tracked it down to a repeatable problem with loading app-laptop/acerhk module. Things work fine without the module being loaded and corrupt the data about once every 5 million computations. Since this is likely some strange interaction of the hardware and/or modules here is some of the specs and notes on the hardware/software: Laptop: Acer 5720z CPU dual-core T2330 2GB ram 160GB SATA HD Intel Graphics with X3100 accelerator Software: Gentoo updated today. kernel gentoo-sources-2.6.24-r7 gcc-4.1.2 CHOST="i686-pc-linux-gnu" Safe processor CFLAGS set to "-march=prescott -O2 -pipe -fomit-frame-pointer" Reproducible always: To reproduce the problem may require a similar Acer laptop, but it is now reproducible. First start by installing gentoo and blender (or any other program which is sensitive to corrupting the data stream). Use blender to run a simple particle simulation. It should work. Now install app-laptop/acerhk and rerun blender, etc. It will likely stall part way through the simulation. Another hint that something is amiss is that sound from music or videos have occasional pops in it, and the KDE windows does strange things on occasion (including freezing). Once the acerhk module is removed the system runs stable. If anyone is interested in looking into this I will be glad to send them my kernel .config file, and instructions for setting up a simple blender particle simulation to aid replication. EBo -- emerge --info to follow Portage 2.1.4.4 (default-linux/x86/2007.0/desktop, gcc-4.1.2, glibc-2.6.1-r0, 2.6.24-gentoo-r7 i686) ================================================================= System uname: 2.6.24-gentoo-r7 i686 Intel(R) Pentium(R) Dual CPU T2330 @ 1.60GHz Timestamp of tree: Mon, 12 May 2008 17:45:02 +0000 app-shells/bash: 3.2_p17-r1 dev-java/java-config: 1.3.7, 2.1.6 dev-lang/python: 2.4.4-r9 dev-python/pycrypto: 2.0.1-r6 sys-apps/baselayout: 1.12.11.1 sys-apps/sandbox: 1.2.18.1-r2 sys-devel/autoconf: 2.13, 2.61-r1 sys-devel/automake: 1.5, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10.1 sys-devel/binutils: 2.18-r1 sys-devel/gcc-config: 1.4.0-r4 sys-devel/libtool: 1.5.26 virtual/os-headers: 2.6.23-r3 ACCEPT_KEYWORDS="x86" CBUILD="i686-pc-linux-gnu" CFLAGS="-march=prescott -O2 -pipe -fomit-frame-pointer" CHOST="i686-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/config /var/lib/hsqldb" CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/fonts/fonts.conf /etc/gconf /etc/php/apache2-php5/ext-active/ /etc/php/cgi-php5/ext-active/ /etc/php/cli-php5/ext-active/ /etc/revdep-rebuild /etc/terminfo /etc/texmf/web2c /etc/udev/rules.d" CXXFLAGS="-march=prescott -O2 -pipe -fomit-frame-pointer" DISTDIR="/usr/portage/distfiles" FEATURES="ccache distlocks metadata-transfer parallel-fetch sandbox sfperms strict unmerge-orphans userfetch" GENTOO_MIRRORS="http://gentoo.osuosl.org/ ftp://distro.ibiblio.org/pub/linux/distributions/gentoo/ http://distro.ibiblio.org/pub/linux/distributions/gentoo/ ftp://ftp.gtlib.gatech.edu/pub/gentoo http://www.gtlib.gatech.edu/pub/gentoo ftp://mirror.iawnet.sandia.gov/pub/gentoo/ ftp://ftp.ussg.iu.edu/pub/linux/gentoo http://cudlug.cudenver.edu/gentoo/ http://gentoo.mirrors.pair.com/ ftp://gentoo.mirrors.pair.com/ http://gentoo.mirrors.tds.net/gentoo ftp://gentoo.mirrors.tds.net/gentoo http://gentoo.netnitco.net ftp://gentoo.netnitco.net/pub/mirrors/gentoo/source/ http://mirror.espri.arizona.edu/gentoo/ http://prometheus.cs.wmich.edu/gentoo http://mirror.mcs.anl.gov/pub/gentoo/ ftp://mirror.mcs.anl.gov/pub/gentoo/ http://gentoo.cites.uiuc.edu/pub/gentoo/ ftp://gentoo.cites.uiuc.edu/pub/gentoo/ http://mirror.fslutd.org/linux/distributions/gentoo/ ftp://mirror.fslutd.org/linux/distributions/gentoo/ nehet" LINGUAS="en" MAKEOPTS="-j4" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage_overlays" SYNC="rsync://rsync.namerica.gentoo.org/gentoo-portage" USE="X a52 aac acl acpi alsa arts audiofile berkdb blender-game bluetooth bzip2 cairo cdr cli cracklib crypt css cups dbus dri dvd dvdr dvdread eds emboss encode esd evo fam ffmpeg firefox fortran ftp gdbm gif gnome gpm gstreamer gtk hal hddtemp hdf5 iconv ieee1394 ipv6 ipw3945 isdnlog java javascript jpeg jpeg2k kde kerberos latex ldap lm_sensors mad midi mikmod mp3 mpeg mudflap ncurses netcdf nls nptl nptlonly ogg openal opengl openmp oss pam pcre pdf perl png pppd python qt3 qt3support qt4 quicktime readline reflection sdl session spell spl ssl svg tcl tcpd threads tiff tk truetype unicode vorbis win32codecs wmf x86 xine xml xorg xv zlib" ALSA_CARDS="hda-intel" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" ELIBC="glibc" INPUT_DEVICES="keyboard mouse synaptics evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="en" USERLAND="GNU" VIDEO_CARDS="i810 vesa" Unset: CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
acerhk is not maintained by upstream anymore, try acer_acpi or in case you use 2.6.25 kernel use in-kernel acer_wmi and see if it supports your hardware well
