Re: [PATCH v2] mmc: core: apply NO_CMD23 quirk to an ATP card

[Christoph Fritz <chf.fritz@googlemail.com>]

On Mon, 2017-09-25 at 11:33 +0800, Shawn Lin wrote:
> >> I'm just curious about if these ATP cards could work for ACMD23?
> >>
> >> Could you kindly try this patch?
> >>
> >> |https://patchwork.kernel.org/patch/9887651/
> > 
> > By looking at your patch I can see that bool variable 'need_acmd23' is
> > only set when card does not support CMD23. But here this card (falsely)
> > claims to support CMD23, which is the whole point of the NO_CMD23 quirk.
> > 
> > So testing your patch would not make any difference, because its
> 
> yup, sorry fot that. I mean you could hack it a little to mask
> CMD23 support and let ACMD23 take effect, and see how it would
> go?

forcing ACMD23 instead of CMD23 works fine:

dd if=/dev/urandom of=/mnt/test bs=1M count=100 conv=fsync
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 9.9496 s, 10.5 MB/s

It's as fast as using my NO_CMD23 quirk.

> >>>>           /*
> >>>> +        * Some SD cards lockup while using CMD23 multiblock transfers.
> >>>> +        */
> >>>> +       MMC_FIXUP("AF SD", CID_MANFID_ATP, CID_OEMID_ANY, add_quirk_sd,
> >>>> +                 MMC_QUIRK_BLK_NO_CMD23),
> >>>
> >>> Is really all ATP cards having this problem? Perhaps we should
> >>> consider making this a bit more fine grained?
> >>>
> >>> On the other hand, this may be the safest way to do it...
> > 
> > I also thought about this and set CID_OEMID_ANY because I wanted to be
> > on the safe side. Maybe ATP can comment on this (in CC)?

Thanks
 -- Christoph