> -----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 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
