Bonjour.
Lorsque que je regle le volume sous gnome et que je sélectione la carte son Sis 7018 Alsa mixer le controleur de son plante et bugBuddy se lance j'avais le meme proble sous fedora7:-(
Voici la sortie de bugBuddy 
Distribution: Fedora release 8 (Werewolf)
Gnome Release: 2.20.3 2008-01-08 (Red Hat, Inc)
BugBuddy Version: 2.20.1

System: Linux 2.6.24.3-50.fc8 #1 SMP Thu Mar 20 14:47:10 EDT 2008 i686
X Vendor: The X.Org Foundation
X Vendor Release: 10300000
Selinux: Permissive
Accessibility: Disabled
GTK+ Theme: Clearlooks
Icon Theme: Clearlooks

Memory status: size: 0 vsize: 0 resident: 0 share: 0 rss: 0 rss_rlim: 0
CPU usage: start_time: 0 rtime: 0 utime: 0 stime: 0 cutime:0 cstime: 0 timeout: 0 it_real_value: 0 frequency: 0



----------- .xsession-errors (26 sec old) ---------------------
(gst-launch-0.10:7357): GStreamer-WARNING **: pad mpegaudioparse0:src returned caps which are not a real subset of its template caps
(gst-launch-0.10:7357): GStreamer-WARNING **: pad mpegaudioparse0:src returned caps which are not a real subset of its template caps
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstAudioSinkClock
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
(gst-launch-0.10:7364): GStreamer-WARNING **: pad mpegaudioparse0:src returned caps which are not a real subset of its template caps
(gst-launch-0.10:7364): GStreamer-WARNING **: pad mpegaudioparse0:src returned caps which are not a real subset of its template caps
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstAudioSinkClock
--------------------------------------------------
Est ce que cela vient de alsa ?
Marci d'avance.
Commande lspci 
00:00.0 Host bridge: Silicon Integrated Systems [SiS] 630 Host (rev 20)
00:00.1 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE] (rev d0)
00:01.0 ISA bridge: Silicon Integrated Systems [SiS] SiS85C503/5513 (LPC Bridge)
00:01.1 Ethernet controller: Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet (rev 81)
00:01.2 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 07)
00:01.3 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 07)
00:01.4 Multimedia audio controller: Silicon Integrated Systems [SiS] SiS PCI Audio Accelerator (rev 02)
00:02.0 PCI bridge: Silicon Integrated Systems [SiS] Virtual PCI-to-PCI bridge (AGP)
00:09.0 Ethernet controller: Atheros Communications, Inc. AR2413 802.11bg NIC (rev 01)
00:0b.0 Ethernet controller: VIA Technologies, Inc. VT6105 [Rhine-III] (rev 86)
00:0d.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 61)
00:0d.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 61)
00:0d.2 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 63)
01:00.0 VGA compatible controller: Silicon Integrated Systems [SiS] 630/730 PCI/AGP VGA Display Adapter (rev 20)
D'après ce que je vois, pour ta carte SIS 630, il faudrait faire un:
modprobe snd-card-trident
(Après édition.)

Et revérifier que les sorties du mixer ne sont pas silencieuses.

Voici mes sources: http://www.alsa-project.org/main/index.php/Matrix:Module-trident

En espérant avoir aidé. Mais si il y a un problème, n'hésites pas, il y a toujours un moyen...