[gentoo-user] No sound. Please, help!

[gevisz]

At different times during the last one and a half years, I tried to
make sound work on my new Gentoo install on a computer with Gigabyte
GA-MA790FXT-UD5P motherboard and MSI ATI Radeon R4770 graphic card.

Previously, I successfully solved the sound problems in Gentoo either
with alsamixer or by compiling the right driver into the kernel but on
this computer these two approaches failed so far.

In my penultimate attempt to solve this problem, I spent no less than
one week trying to compile the right driver into the then 4th Linux
kernel with no result. At the beginning, I managed to get a sound from
this computer after some kernel configurations but they turned out to
be unstable in the sense that later the same kernel configurations
resulted in no sound. (I have used git to control all my experiments
with the kernel configurations, so I am quite sure that configurations
of the kernel for which I sometimes got the sound and later did not
was indeed the same.) My first explanation to this phenomena was that
after recompiling a kernel I also have to recompile xorg-server and
some sound related packages. So I have tried this with no result
again. And, of course, I have always used alsamixer to make sure that
no sound channels are muted.

Finally, I decided that I just cannot find the right combination of
sound drivers and gave up because at that time I could not spend on
this more than one week.

But last month I found out about the gentoo-kernel package and decided
to try once more. I was almost sure that, after installing this
package, I will finally get the sound. So, I have installed the
latest, 5.4.64, version of this package. As a result, the computer
rebooted in the new Linux kernel and everything worked and still works
like a charm except for the sound as it is still absent. :(

So I definitely (and desperately) need your help and promise to follow
all your suggestions. (But, please, take into account that I can
compile on this computer only during weekends.)

As the following command shows

lspci | grep "Audio"
00:14.2 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] SBx00
Azalia (Intel HDA)
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] RV710/730
HDMI Audio [Radeon HD 4000 series]

This computer has two sound devices. The first of them, SBx00 Azalia,
is probably built into the motherboard, and it is where I am trying to
get a sound from. The second one is probably built into the Radeon
graphic card and I am not going to use it at all unless it can output
the sound through the motherboard audio jacks.

My current kernel configuration is exactly the same as in the
gentoo-kernel-5.4.64 package as I have not changed anything there.

And finally: installed on the same computer legacy operating system
never had any sound problems.