Can confirm it works! The ALC287_FIXUP_LEGION_15IMHG05_SPEAKERS makes both speakers work on the 15IMH5, stereo sound. It does require a suspend/wakeup cycle first though.

On another note, the screen brightness controls on this device also have the same issue: they only work after a suspend/wakeup cycle.

It's usable though, better than nothing. Would this be good enough to be added to the main kernel? If that's ok I can also do it, more for the educational value than anything :) With appropriate credit to Cameron Berkenpas of course.

(In reply to Andrei Miculita from comment #631)
> Quick update: it works! sort of...
> 
> I applied the first fixup (LEGION_15IMHG05), but it didn't work, and the
> second (YOGA7_14ITL) didn't either. But while booted from the kernel with
> the 2nd fixup, I decided to give it a quick suspend/wakeup cycle. After the
> wakeup, there is sound! But only from the left speaker. The sound is coming
> only from the left channel.
> 
> I will report back after retrying the 1st fixup, this time with a
> suspend/wakeup cycle.
> 
> (In reply to Cameron Berkenpas from comment #602)
> > Created attachment 300990 [details]
> > attachment-14829-0.html
> > 
> >  From your alsa-info (thanks!), I see that your subsystem id is 0x3822 
> > compared to the 0x1813 of the 15IMHG05.
> > 
> > In the root of the linux source folder/directory, open the file:
> > sound/pci/hda/patch_realtek.c
> > 
> > Find this line:
> > SND_PCI_QUIRK(0x17aa, 0x3813, "Legion 7i 15IMHG05", 
> > ALC287_FIXUP_LEGION_15IMHG05_SPEAKERS),
> > 
> > Next to that line (before or after doesn't matter), add your own line:
> > SND_PCI_QUIRK(0x17aa, 0x3822, "Legion 7i 15IMH5", 
> > ALC287_FIXUP_LEGION_15IMHG05_SPEAKERS),
> > 
> > If the ALC287_FIXUP_LEGION_15IMHG05_SPEAKERS fix doesn't work for your 
> > laptop, try theALC287_FIXUP_YOGA7_14ITL_SPEAKERS fix as well. Ie,
> > SND_PCI_QUIRK(0x17aa, 0x3822, "Legion 7i 15IMH5", 
> > ALC287_FIXUP_YOGA7_14ITL_SPEAKERS),
> > 
> > But given the similarities between our laptop models, I strongly suspect 
> > the 15IMHG05 fix will work for your laptop as well.
> > 
> > Looks like you're running linux Mint, which, IIRC, is based on Debian or 
> > Ubuntu. For deb based distributions, you can build packages for your 
> > kernel like this:
> > make bindeb-pkg
> > 
> > You only really need the linux-image and linux-headers (for Nvidia) 
> > packages. To speed up the compile, you can pass in the -j option to 
> > parallelize the build:
> > make -j$(nproc) bindeb-pkg
> > 
> > 
> > On 5/17/22 14:32, <email address hidden> wrote:
> > > https://bugzilla.kernel.org/show_bug.cgi?id=208555
> > >
> > > --- Comment #601 from Andrei Miculita (<email address hidden>) ---
> > > (In reply to Cameron Berkenpas from comment #600)
> > >> Looking at the model number, there's a chance it's compatible with the
> > >> verbs of the 15IMHG05, or another model from around that time.
> > >>
> > >> Do you know how to build and run your own kernel?
> > >>
> > >> Also, please provide a URL to your alsa-info.
> > >>
> > >> On 5/15/2022 12:12 PM,<email address hidden>  wrote:
> > >>> https://bugzilla.kernel.org/show_bug.cgi?id=208555
> > >>>
> > >>> --- Comment #599 from Andrei Miculita (<email address hidden>)
> ---
> > >>> Lenovo Legion S7 15IMH5
> > >>>
> > >>> Has anyone managed to get their sound working on it? Would appreciate a
> > >>> tutorial or some tips (the more specific, the better, as this thread is
> > >> full
> > >>> of
> > >>> other devices as well and it'd take a long time to try everything)
> > >>>
> > >
> > > I do, it might take me a while to get it done if I start now, but I've
> done
> > > it
> > > before for fun.
> > >
> > >
> > > My alsa-info:
> > > http://alsa-project.org/db/?f=c1ba1098da13b2d7d6793fbce823e4feed2ac4ee
> > >