Re: [PATCH 5.4] Revert "ARM: dts: Move am33xx and am43xx mmc nodes to sdhci-omap driver"

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Nov 06, 2023 at 10:50:48AM +0100, Matthias Schiffer wrote:
> This reverts commit d0c69c722ff16ce2481a5e0932c6d5b172109f21.
> 
> The reverted commit completely breaks MMC on the AM33xx/AM437x for
> multiple reasons:
> 
> - The changed compatible strings ti,am335-sdhci and ti,am437-sdhci
>   aren't supported on Linux 5.4 at all, so no driver is found
> - Even when additionally backporting the support for these compatible
>   strings in the sdhci-omap driver, I could not the the MMC interfaces
>   to work on our TQMa335x SoM - the interface would time out during card
>   initialization for both an eMMC and an SD card.
> 
> I did not investigate the cause of the timeouts further, and instead
> just reverted the commit - switching to a different MMC driver in a stable
> kernel seems like a rather risky change unless it's thoroughly tested,
> which has obviously not happened in this case.
> 
> The reverted commit is also given as a Stable-dep-of commit 2eb502f496f7
> ("ARM: dts: am33xx: Fix MMCHS0 dma properties"), however the conflict
> resulting when only the one commit is reverted is trivial to resolve,
> which leads to working MMC controllers again.
> 
> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---
> 
> I have not checked if other stable kernels exhibit the same breakage; it
> might be a good idea to revert the change for all stable branches unless
> it is proven that the sdhci-omap driver actually works.

This was only backported to 5.4.y, thanks for catching this, now queued
up.

greg k-h