no sound after updating to Ubuntu 11.04

[Tycdum]

Ubuntu used to work very well until I had an advice from the update manager to upgrade Ubuntu to 11.04. Since I have no more sound. I have made all the advised tests described in FAQS from terminal and nothing is abnormal, I remain with no sound effect, no more sound with music, with empathy internet messaging etc.

What can I do?
Thanks to you all

[Tycdum (tycdum)]

after a month trials I received this last comment: At least in my case this was the final solution since the ubuntu-team seems to not even consider this a real bug.

see my system testing:
SVG_Color_Image_Xubuntu.svg_testskipped list_audio_devicesPASSED playback_autoFAILED playback_headphonesFAILED alsa_record_playback_internalFAILED alsa_record_playback_external
Log Files and Environment Information
cat /proc/asound/card*/codec#*
cat /proc/cpuinfo
cat /var/log/dmesg | ansi_parser
grep -r . /sys/class/dmi/id/ 2>/dev/null
dmidecode
lspci -vvnn
find /etc/modprobe.* -name \*.conf | xargs cat
cat /etc/modules
find /etc/sysctl.* -name \*.conf | xargs cat
udevadm info --export-db
gcov_tarball
lsmod
Aplay -l me donne

card 0: ICH6 [Intel ICH6], device 0: Intel ICH [Intel ICH6]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: ICH6 [Intel ICH6], device 4: Intel ICH - IEC958 [Intel ICH6 - IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: CA0106 [CA0106], device 0: ca0106 [CA0106]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: CA0106 [CA0106], device 1: ca0106 [CA0106]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: CA0106 [CA0106], device 2: ca0106 [CA0106]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: CA0106 [CA0106], device 3: ca0106 [CA0106]
  Subdevices: 1/1
  Subdevice #0: subdevice #0