AML-S905X-CC-V2 emmc issue

[Ferass El Hafidi]

Hi,

On Tue Apr 29, 2025 at 6:59 PM UTC, Jeff Sacksteder wrote:
> I'm having a problem trying to install Alpine Linux on to a Libre
> Computing Sweet Potato AML-S905X-CC-V2 and I need some clairification,
> if someone has been down this road already.
>
> The sd card is detected, but the optional emmc module is not(per dmesg
> and /dev/mmc*).
>
> The suggested distros Libre suggests work correctly, so I know the
> hardware is good.
>
> I don't know if they have magic patches, so looking for clues
> elsewhere, the current Gentoo image for Arm correctly detects both
> devices.
>
> The first obvious difference I find vs Alpine is that they include
> PWRSEQ_EMMC compiled as a module, while Alpine does not configure that
> option at all. My operating theory is that this hardware needs some
> bring-up power negotiation before it is available.
>
> However, since I don't have a cross-compile environment available, and
> it takes 35 hrs to build a kernel, and the Alpine build process is
> convoluted and weird to me, I would really like to know if that single
> option is the solution. Otherwise I face multiple 35 hr cycles of
> building and testing.

Last time I tried Alpine's linux-edge kernel (was on an S905 board), my SD 
card was not being detected correctly either.  I also suspect missing
things in the kernel's config.  For reference, this is the kconfig
postmarketOS uses:

https://gitlab.postmarketos.org/postmarketOS/pmaports/-/blob/4c0787f38f74a089f1140f85ba980da91fc48016/device/testing/linux-postmarketos-amlogic/config-postmarketos-amlogic.aarch64

No patches are required to get the module working.

When I tested it, the eMMC module works perfectly fine on all my Libre
Computer boards (alta, solitude, lepotato, lafrite).  I've no doubt it
should work on sweetpotato as well.

Cheers.