I guess this sounds rather weird, but since it happens on both my Gentoo systems I decided to post this here: I activated desktop device icons in KDE (Control Center/Desktop/Behavior/Device Icons), so I could conveniently access hot-pluggable devices, e.g. USB sticks. Combined with hal this works just brilliantly, if it weren't for one annoying detail: Whenever I mount or unmount one of the displayed devices while at the same time playing an audio CD, the playback randomly skips to another track or stops playing at all. It doesn't matter whether I mount the device by clicking the icon or by entering the mount command in a terminal -- as soon as the desktop icon is updated to display the new device state CD playback is affected. You'd think that this effect would be noticed rather quickly, but I didn't found any mention of it. So I guess it's something specific to my configuration, I just haven't got any clue where to start searching. It happens on both my desktop (with KDE 3.4.1) and my laptop (with KDE 3.4.3). Finally, the obligatory "emerge --info": Portage 2.0.54 (default-linux/x86/2005.0, gcc-3.3.6, glibc-2.3.5-r2, 2.6.13.3 i686) ================================================================= System uname: 2.6.13.3 i686 AMD Duron(tm) Processor Gentoo Base System version 1.6.14 dev-lang/python: 2.3.5-r2, 2.4.2 sys-apps/sandbox: 1.2.12 sys-devel/autoconf: 2.13, 2.59-r6 sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r1 sys-devel/binutils: 2.16.1 sys-devel/libtool: 1.5.22 virtual/os-headers: 2.4.19-r1, 2.6.11-r2 ACCEPT_KEYWORDS="x86" AUTOCLEAN="yes" CBUILD="i686-pc-linux-gnu" CFLAGS="-O2 -march=athlon -pipe" CHOST="i686-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.4/env /usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config /usr/lib/X11/xkb /usr/lib/mozilla/defaults/pref /usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/share/texmf/xdvi/ /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-O2 -march=athlon -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="autoconfig distlocks sandbox sfperms strict" GENTOO_MIRRORS="ftp://ftpl.tu-chemnitz.de/pub/linux/gentoo" MAKEOPTS="-j2" PKGDIR="/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" SYNC="rsync://rsync.de.gentoo.org/gentoo-portage" USE="x86 3dnow X aalib acl alsa apm audiofile avi bash-completion berkdb bitmap-fonts bonobo bzip2 cdr crypt cups curl dga dvd dvdr eds emboss encode esd ethereal exif expat fam ffmpeg fortran gd gdbm gif glut gmp gnome gpm gstreamer gtk gtk2 gtkhtml guile hal icq idn imagemagick imap imlib ipv6 java jpeg junit kde lcms ldap libg++ libwww lirc lua mad maildir mbox mikmod mmx mng motif mozilla moznoirc moznomail mozsvg mp3 mpeg ncurses nls ogg oggvorbis openal opengl oss pam pcre pdflib perl png postgres python qt quicktime readline recode samba sasl sdl slang spell ssl tcltk tcpd tetex tiff truetype truetype-fonts type1-fonts udev unicode usb v4l2 vim-with-x vorbis win32codecs xaw3d xine xml xml2 xmms xosd xv xvid zlib userland_GNU kernel_linux elibc_glibc" Unset: ASFLAGS, CTARGET, LANG, LC_ALL, LDFLAGS, LINGUAS
Assuming you're using ALSA, try if increasing the buffer size (/etc/asound.conf or it's user local pendant) to 4k, 8, 16k helps.
(In reply to comment #1) > Assuming you're using ALSA, try if increasing the buffer size (/etc/asound.conf > or it's user local pendant) to 4k, 8, 16k helps. Thanks for the hint, but this is definitely not an ALSA problem -- I'm not even using digital playback. And the CD playback always skips to the start of another track (unless it stops completely), so this is certainly not a matter of timing or empty buffers.
OK, I did a little investigation: KDE performs several ioctl's on the devices in /etc/fstab whenever anything is mounted or unmounted (e.g. CDROMREADTOCHDR, CDROM_DRIVE_STATUS and CDROM_DISC_STATUS). One of those seems to disturb audio playback. The effect does not occur if I either remove the cdrom entry from /etc/fstab or if I revoke write permissions for the cdrom device from my uid.
Guess I found the reason for this unusual behaviour; the ioctl's I suspected in my previous comment are innocent, and so is the KDE base library. The problem seems to be the kio_audiocd slave, which uses the cdparanoia library to perform digital reads on audio CDs. Unfortunately cdparanoia performs a single test read upon initialization, leading to rather strange effects when the drive is alreay busy playing back a CD. So, this is KDE's fault, not Gentoo's. Gonna change the resolution field to UPSTREAM and go on nagging the KDE people instead.
