Hi Bing, sdhci_add_host() reads host controller's capabilities and initialize host->caps of function mmc_host_uhs(). So mmc_host_uhs() only return this cached values. Thanks, Jackey -----Original Message----- From: Bing Zhao [mailto:bzhao@xxxxxxxxxxx] Sent: Thursday, December 06, 2012 3:14 AM To: Shen, Jackey; Subhash Jadavani; linux-mmc@xxxxxxxxxxxxxxx Cc: linux-arm-msm@xxxxxxxxxxxxxxx; Sujit Reddy Thumma Subject: RE: [PATCH v1 2/3] mmc: sdio: Fix SDIO 3.0 UHS-I initialization sequence Hi Jackey, > Hi Bing, > > The function mmc_host_uhs() will return false and never set bit[24] (S18R) for SDIO 2.0 cards. I thought mmc_host_uhs() will return host controller's capabilities, no? Thanks, Bing > > Thanks, > Jackey > > -----Original Message----- > From: linux-mmc-owner@xxxxxxxxxxxxxxx > [mailto:linux-mmc-owner@xxxxxxxxxxxxxxx] On Behalf Of Bing Zhao > Sent: Wednesday, December 05, 2012 5:14 AM > To: Subhash Jadavani; linux-mmc@xxxxxxxxxxxxxxx > Cc: linux-arm-msm@xxxxxxxxxxxxxxx; Sujit Reddy Thumma > Subject: RE: [PATCH v1 2/3] mmc: sdio: Fix SDIO 3.0 UHS-I > initialization sequence > > Hi, > > > From: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx> > > > > 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 <sthumma@xxxxxxxxxxxxxx> > > Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx> > > --- > > drivers/mmc/core/sdio.c | 22 +++++++++++----------- > > include/linux/mmc/host.h | 8 ++++++++ > > 2 files changed, 19 insertions(+), 11 deletions(-) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" > in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo > info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
