> -----Original Message----- > From: Nath, Arindam > Sent: Saturday, August 06, 2011 12:27 AM > To: 'Subhash Jadavani'; 'linux-mmc@xxxxxxxxxxxxxxx' > Cc: 'Chris Ball'; 'Philip Rakity'; 'zhangfei gao' > Subject: RE: Issue with non-UHS-I SD3.0 cards > > > > > -----Original Message----- > > From: Nath, Arindam > > Sent: Saturday, August 06, 2011 12:15 AM > > To: 'Subhash Jadavani'; linux-mmc@xxxxxxxxxxxxxxx > > Cc: 'Chris Ball'; 'Philip Rakity'; 'zhangfei gao' > > Subject: RE: Issue with non-UHS-I SD3.0 cards > > > > Hi Subhash, > > > > > > > -----Original Message----- > > > From: Subhash Jadavani [mailto:subhashj@xxxxxxxxxxxxxx] > > > Sent: Friday, August 05, 2011 7:01 PM > > > To: linux-mmc@xxxxxxxxxxxxxxx > > > Cc: Nath, Arindam; 'Chris Ball'; 'Philip Rakity'; 'zhangfei gao' > > > Subject: Issue with non-UHS-I SD3.0 cards > > > > > > Hi, > > > > > > I am seeing the issue where "SanDisk Extreme SDHC 8GB Class 10 > card" > > is > > > running in "Default Speed" mode even though it supports "High > Speed" > > > mode. > > > After analysis, I found that this card is advertising itself as > SD3.0 > > > card > > > (with SD_SPEC=2 and SD_SPEC3=1 in SCR). But current mmc core later > > > initialization sequence for SD3.0 cards is such that these non-UHS- > I > > > SD3.0 > > > cards runs in Default Speed mode @25MHz. > > > > > > Here is Essential conditions to indicate Version 3.00 Card (from > > SD3.01 > > > spec) > > > (SD_SPEC=2 and SD_SPEC3=1) : > > > (1) The card shall support CMD6 > > > (2) The card shall support CMD8 > > > (3) The card shall support CMD42 > > > (4) User area capacity shall be up to 2GB (SDSC) or 32GB (SDHC) > > > User area capacity shall be more than or equal to 32GB and > > > up to 2TB (SDXC) > > > (5) Speed Class shall be supported (SDHC or SDXC) > > > > I went through the particular section of the spec again, and IMO, the > > essential conditions are for the manufacturer of the card to > advertise > > his card as SD3.0 card or otherwise. From software point of view, the > > SD_SPEC=2 _and_ SD_SPEC3=1 will indicate a SD3.0 card. > > I misread your comment, so please ignore what you mentioned above. So *so please ignore what I mentioned above* Sorry for the typo. > if I understand correctly, in your case *sd_spec3* is set for the card, > even though it is a non UHS-I card. In that case, what you tried in > your patch looks fine, except that I would suggest to move it inside > the > > if (card->scr.sda_spec3) { > ... > } > > condition. > > > > > Thanks, > > Arindam > > > > > > > > > > > So even if SD card doesn't support any of the newly defined UHS-I > bus > > > speed > > > mode, it can advertise itself as SD3.0 cards as long as it supports > > all > > > the > > > essential conditions of SD3.0 cards. Given this, these type of > cards > > > should > > > at least run in High Speed mode @50MHZ if it supports HS. > > > > > > Here are the changes you have to do to make non-UHS-I SD3.0 cards > run > > > in > > > High Speed Mode @50MHz. Do let me know if looks fine or not, so I > can > > > post > > > the formal patch. > > > > > > --- > > > drivers/mmc/core/sd.c | 6 +++--- > > > 1 files changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > > > index 907662a..3fab676 100644 > > > --- a/drivers/mmc/core/sd.c > > > +++ b/drivers/mmc/core/sd.c > > > @@ -305,6 +305,9 @@ static int mmc_read_switch(struct mmc_card > *card) > > > goto out; > > > } > > > > > > + if (status[13] & 0x02) > > > + card->sw_caps.hs_max_dtr = 50000000; > > > + > > > if (card->scr.sda_spec3) { > > > card->sw_caps.sd3_bus_mode = status[13]; > > > > > > @@ -347,9 +350,6 @@ static int mmc_read_switch(struct mmc_card > *card) > > > } > > > > > > card->sw_caps.sd3_curr_limit = status[7]; > > > - } else { > > > - if (status[13] & 0x02) > > > - card->sw_caps.hs_max_dtr = 50000000; > > > } > > > > > > out: > > > -- > > > > > > > > > Regards, > > > Subhash > > > > > > -- 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
