regression on rk3288 with - mmc: dw_mmc: Remove old card detect infrastructure

[Doug Anderson]

Hi,

On Fri, Dec 12, 2014 at 12:22 PM, Heiko Stübner <heiko at sntech.de> wrote:
> Hi,
>
> when trying linux-next for 20141210 on my rk3288 eval board I got errors
> when ejecting sd cards. Especially a timeout for a command and following
> this an rcu stall which essentially stops everything [0].
>
> My way to reproduce the issue is:
> - boot into an initramfs
> - insert card
> - remove card
> - boom
>
> It happens 100% of the time on the first removal of the card.
>
>
> Bisecting the issue brought me to
>
> first bad commit
> 6130e7a9c34d01afbd4e7e215846d1f2d70333bb
> mmc: dw_mmc: Remove old card detect infrastructure
>
> and indeed if I revert this one, card ejection works again - also multiple
> times in a row. Affected machine is a rk3288-evb-rk808 board which
> currently uses the internal card-detect mechanism of the dw_mmc and
> relevant git history (--oneline) is:
>
> 864de9b Revert "mmc: dw_mmc: Remove old card detect infrastructure"
> 5bd48e0 ARM: dts: Bump SD card pin drive strength up on rk3288-evb
> 12fd072 Add linux-next specific files for 20141210
> ...
>
>
> I'll try to dig deeper, but if anybody has ideas beforehand I would also
> be very glad.

I tried to reproduce this on the same board on 20141211.  I have a
different bootloader, but I hope that doesn't matter?

git describe
next-20141211-1-gf8afbb8

$ git log --oneline next-20141211~..
f8afbb8 FROMLIST: ARM: dts: Bump SD card pin drive strength up on rk3288-evb
291ca61 Add linux-next specific files for 20141211


In inserted 3 different cards into the SD card slots (a micro UHS, an
older micro one, and a full sized UHS).  I inserted / ejected each one
several times.

Could it be a different set of kernel config options?  That's about
the best guess I can come up with...