I can confirm this problem. Sound with kernel 2.6.24-11-generic works, but it doesn't work in kernel 2.6.24-12-generic any more. dmesg gives the following error messages regarding the modules for the sound card: [ 41.323834] snd_hwdep: Unknown symbol snd_info_register [ 41.323860] snd_hwdep: Unknown symbol snd_info_create_module_entry [ 41.323885] snd_hwdep: Unknown symbol snd_ctl_unregister_ioctl_compat [ 41.323909] snd_hwdep: Unknown symbol snd_info_free_entry [ 41.323939] snd_hwdep: Unknown symbol snd_unregister_oss_device [ 41.323967] snd_hwdep: Unknown symbol snd_verbose_printk [ 41.323991] snd_hwdep: Unknown symbol snd_register_oss_device [ 41.324017] snd_hwdep: Unknown symbol snd_ctl_register_ioctl [ 41.324041] snd_hwdep: Unknown symbol snd_card_file_add [ 41.324072] snd_hwdep: Unknown symbol snd_iprintf [ 41.324096] snd_hwdep: Unknown symbol snd_major [ 41.324130] snd_hwdep: Unknown symbol snd_unregister_device [ 41.324156] snd_hwdep: Unknown symbol snd_device_new [ 41.324189] snd_hwdep: Unknown symbol snd_ctl_unregister_ioctl [ 41.324220] snd_hwdep: Unknown symbol snd_lookup_oss_minor_data [ 41.324247] snd_hwdep: Unknown symbol snd_lookup_minor_data [ 41.324272] snd_hwdep: Unknown symbol snd_ctl_register_ioctl_compat [ 41.324298] snd_hwdep: Unknown symbol snd_card_file_remove [ 41.324322] snd_hwdep: Unknown symbol snd_register_device_for_dev [ 41.355939] snd_timer: Unknown symbol snd_info_register [ 41.355966] snd_timer: Unknown symbol snd_info_create_module_entry [ 41.355995] snd_timer: Unknown symbol snd_info_free_entry [ 41.356045] snd_timer: Unknown symbol snd_verbose_printk [ 41.356077] snd_timer: Unknown symbol snd_iprintf [ 41.356115] snd_timer: Unknown symbol snd_ecards_limit [ 41.356144] snd_timer: Unknown symbol snd_oss_info_register [ 41.356168] snd_timer: Unknown symbol snd_unregister_device [ 41.356198] snd_timer: Unknown symbol snd_device_new [ 41.356259] snd_timer: Unknown symbol snd_register_device_for_dev ... [ 41.502891] snd: Unknown symbol unregister_sound_special [ 41.502981] snd: Unknown symbol register_sound_special_device [ 41.503267] snd: Unknown symbol sound_class ... [ 41.504126] snd_timer: Unknown symbol snd_info_register [ 41.504152] snd_timer: Unknown symbol snd_info_create_module_entry [ 41.504181] snd_timer: Unknown symbol snd_info_free_entry [ 41.504231] snd_timer: Unknown symbol snd_verbose_printk [ 41.504264] snd_timer: Unknown symbol snd_iprintf [ 41.504302] snd_timer: Unknown symbol snd_ecards_limit [ 41.504331] snd_timer: Unknown symbol snd_oss_info_register [ 41.504356] snd_timer: Unknown symbol snd_unregister_device [ 41.504386] snd_timer: Unknown symbol snd_device_new [ 41.504447] snd_timer: Unknown symbol snd_register_device_for_dev [ 41.520860] snd_pcm: Unknown symbol snd_info_register [ 41.520888] snd_pcm: Unknown symbol snd_info_create_module_entry [ 41.520913] snd_pcm: Unknown symbol snd_ctl_unregister_ioctl_compat [ 41.520961] snd_pcm: Unknown symbol snd_timer_notify [ 41.520994] snd_pcm: Unknown symbol snd_timer_interrupt [ 41.521018] snd_pcm: Unknown symbol snd_info_free_entry [ 41.521043] snd_pcm: Unknown symbol snd_add_device_sysfs_file [ 41.521075] snd_pcm: Unknown symbol snd_info_get_str [ 41.521140] snd_pcm: Unknown symbol snd_verbose_printk [ 41.521197] snd_pcm: Unknown symbol snd_ctl_register_ioctl [ 41.521222] snd_pcm: Unknown symbol snd_card_file_add [ 41.521253] snd_pcm: Unknown symbol snd_iprintf [ 41.521294] snd_pcm: Unknown symbol snd_major [ 41.521351] snd_pcm: Unknown symbol snd_unregister_device [ 41.521381] snd_pcm: Unknown symbol snd_timer_new [ 41.521406] snd_pcm: Unknown symbol snd_device_new [ 41.521454] snd_pcm: Unknown symbol snd_ctl_unregister_ioctl [ 41.521496] snd_pcm: Unknown symbol snd_lookup_minor_data [ 41.521521] snd_pcm: Unknown symbol snd_ctl_register_ioctl_compat [ 41.521556] snd_pcm: Unknown symbol snd_info_create_card_entry [ 41.521581] snd_pcm: Unknown symbol snd_power_wait [ 41.521610] snd_pcm: Unknown symbol snd_device_free [ 41.521653] snd_pcm: Unknown symbol snd_card_file_remove [ 41.521678] snd_pcm: Unknown symbol snd_register_device_for_dev [ 41.521739] snd_pcm: Unknown symbol snd_device_register [ 41.521765] snd_pcm: Unknown symbol snd_info_get_line ... [ 39.216852] snd_hda_intel: Unknown symbol snd_ctl_add [ 39.216889] snd_hda_intel: Unknown symbol snd_pcm_new [ 39.216923] snd_hda_intel: Unknown symbol snd_pcm_limit_hw_rates [ 39.216951] snd_hda_intel: Unknown symbol snd_card_register [ 39.216976] snd_hda_intel: Unknown symbol snd_card_free [ 39.217001] snd_hda_intel: Unknown symbol snd_pcm_lib_preallocate_pages_for_all [ 39.217027] snd_hda_intel: Unknown symbol snd_card_proc_new [ 39.217113] snd_hda_intel: Unknown symbol snd_ctl_find_id [ 39.217148] snd_hda_intel: Unknown symbol snd_verbose_printk [ 39.217193] snd_hda_intel: Unknown symbol snd_ctl_new1 [ 39.217250] snd_hda_intel: Unknown symbol snd_component_add [ 39.217282] snd_hda_intel: Unknown symbol snd_card_new [ 39.217307] snd_hda_intel: Unknown symbol snd_iprintf [ 39.217335] snd_hda_intel: Unknown symbol snd_pcm_lib_malloc_pages [ 39.217360] snd_hda_intel: Unknown symbol snd_ctl_boolean_mono_info [ 39.217394] snd_hda_intel: Unknown symbol snd_pcm_lib_ioctl [ 39.217422] snd_hda_intel: Unknown symbol snd_pcm_lib_free_pages [ 39.217446] snd_hda_intel: Unknown symbol snd_hwdep_new [ 39.217476] snd_hda_intel: Unknown symbol snd_pcm_set_ops [ 39.217508] snd_hda_intel: Unknown symbol snd_pcm_hw_constraint_list [ 39.217541] snd_hda_intel: Unknown symbol snd_device_new [ 39.217581] snd_hda_intel: Unknown symbol snd_pcm_suspend_all [ 39.217617] snd_hda_intel: Unknown symbol snd_card_disconnect [ 39.217643] snd_hda_intel: Unknown symbol snd_pcm_hw_constraint_integer [ 39.217713] snd_hda_intel: Unknown symbol snd_pci_quirk_lookup [ 39.217775] snd_hda_intel: Unknown symbol snd_pcm_period_elapsed [ 39.217801] snd_hda_intel: Unknown symbol snd_pcm_hw_constraint_step [ 39.217845] snd_hda_intel: Unknown symbol snd_pcm_format_width Interestingly, if I do a 'dpkg -S "snd-hda-intel*"', I get the following: linux-ubuntu-modules-2.6.24-11-generic: /lib/modules/2.6.24-11-generic/ubuntu/sound/alsa-driver/pci/hda/snd-hda-intel.ko linux-image-2.6.24-11-generic: /lib/modules/2.6.24-11-generic/kernel/sound/pci/hda/snd-hda-intel.ko linux-ubuntu-modules-2.6.24-12-generic: /lib/modules/2.6.24-12-generic/ubuntu/sound/alsa-driver/pci/hda/snd-hda-intel.ko Are there some modules missing in the main kernel package?