under newer hand-rolled kernel, sound has gone away on ubuntu 11.04

[Robert P. J. Day]

  technically speaking, not a ubuntu issue but i'm hoping someone here
can point me in the right direction.  under my earlier
2.6.39-rc7-dirty kernel on 10.10, sound on my gateway NV79 laptop just
plain worked.  under that earlier kernel, here's the output of a
couple commands:

$lspci -v
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05)
        Subsystem: Acer Incorporated [ALI] Device 031c
        Flags: bus master, fast devsel, latency 0, IRQ 42
        Memory at d4400000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: <access denied>
        Kernel driver in use: HDA Intel
        Kernel modules: snd-hda-intel

$ cat /proc/asound/card0/codec* | grep Codec
Codec: Realtek ALC272X
Codec: Conexant ID 2c06
Codec: Intel IbexPeak HDMI

  also, System->Preferences->Sound, "Hardware" showed:

    Internal Audio
    1 Output / 1 Input
    Analog Stereo Duplex

and "Test Speakers" worked fine, as did all other sound-related apps.

  now, having updated my kernel source and built and booted to a new
kernel on 11.04:

$ uname -r
3.0.0-rc3-00165-gf8f44f0-dirty
$

my sound has vanished.  no youtube, no playing music CDs, etc.

  the output of "lspci -v" and checking under /proc as above shows
exactly the same output, but if i go under System->Preferences->Sound
and look under the "Hardware" tab, it's *empty*, so there's nothing to
select and test.

  based on what i've read, it seems that one possible solution is to
edit the file /etc/modprobe.d/alsa-base.conf and, in my case, add a
line of the form

  options snd-hda-intel model=????

then run "sudo alsa force-reload" to reload all the modules.  but
i've tried several choices: generic, auto, and a few others, and
nothing's worked.

  i'm open to suggestions.  clearly, it's a very bad thing that
there's nothing listed under sound hardware, but i don't know how to
reconfigure to get it back.  thoughts?

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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