Hi Bing,

The function mmc_host_uhs() will return false and never set bit[24] (S18R) for 
SDIO 2.0 cards.

Thanks,
Jackey

-----Original Message-----
From: [email protected] [mailto:[email protected]] 
On Behalf Of Bing Zhao
Sent: Wednesday, December 05, 2012 5:14 AM
To: Subhash Jadavani; [email protected]
Cc: [email protected]; Sujit Reddy Thumma
Subject: RE: [PATCH v1 2/3] mmc: sdio: Fix SDIO 3.0 UHS-I initialization 
sequence

Hi,

> From: Sujit Reddy Thumma <[email protected]>
> 
> According to UHS-I initialization sequence for SDIO 3.0 cards, the 
> host must set bit[24] (S18R) of OCR register during OCR handshake to 
> know whether the SDIO card is capable of doing 1.8V I/O.

In SDIO 2.0 spec, bit[24] is reserved, "shall be set to 0".
Setting it to 1 might cause side effect to 2.0 cards.
Perhaps using a quirk for S18R is more suitable for all combinations.

Regards,
Bing

> 
> Signed-off-by: Sujit Reddy Thumma <[email protected]>
> Signed-off-by: Subhash Jadavani <[email protected]>
> ---
>  drivers/mmc/core/sdio.c  |   22 +++++++++++-----------
>  include/linux/mmc/host.h |    8 ++++++++
>  2 files changed, 19 insertions(+), 11 deletions(-)

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