[regression, bisected] no MMC on rk3399-gru-kevin with 5.10-rc1

[Doug Anderson]

Hi,

On Mon, Nov 2, 2020 at 7:02 AM Ulf Hansson <ulf.hansson at linaro.org> wrote:
>
> On Fri, 30 Oct 2020 at 23:04, Vicente Bergas <vicencb at gmail.com> wrote:
> >
> > Hi,
> > commit 21b2cec61c04bd175f0860d9411a472d5a0e7ba1
> > mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.4
> > broke booting rk3399-gru-kevin.
> >
> > The kernel waits forever for the root device to appear on MMC.
>
> Waiting forever sounds weird to me.
>
> > Removing the line containing PROBE_PREFER_ASYNCHRONOUS in
> > drivers/mmc/host/dw_mmc-rockchip.c fixes the issue.
>
> I am guessing when we enable async probe, we reveal some other
> existing error. Or, perhaps the rootfs mount point become wrong?
>
> Would it be possible to share a boot log (before/after) with some
> driver probe debugging enabled?

Are you sure you haven't just got your MMC block IDs shuffled now?
Perhaps a careful application of the newly-supported MMC aliases would
help fix things?  When we landed, Ulf pointed to:

[1]
https://patchwork.kernel.org/patch/11747669/
https://patchwork.kernel.org/patch/11747671/

The async probe can cause shuffling of block IDs which were previously
quite stable though never guaranteed (everyone always yelled loudly
"use UUIDs").

I will also note that I just put v5.10-rc1 on a rk3399-gru-kevin and
confirmed that it booted up OK.

-Doug



-Doug