Hi, Any comments on below mentioned query? Thanks Sujit On Thu, Dec 23, 2010 at 1:35 PM, Sujit Reddy <sujitreddy243@xxxxxxxxx> wrote: > Hi, > > According to eMMC spec v4.3, Section 6.1 says that greater than 2GB > density cards are sector addressable and less than 2GB are byte addressable. > But Section 7.3.3 says that OCR bit 30 needs to be used which access mode > the host must use for all its future transactions. > > In mainline kernel the support for less than 2GB cards is by checking > the density of card. > If it is greater than 2GB it is assumed to be supporting sector addressing. > > But actually we need to check the OCR value to determine the correct access mode > See patch (http://www.spinics.net/lists/linux-mmc/msg01466.html) by Philip. > > Some eMMC cards even though less than 2GB have SEC_COUNT value defined > in EXT_CSD register but does not support sector access mode. > > I have a couple of questions here: > 1) Are there any cards that support only byte access mode even though > the density is > greater than 2GB? > 2) If there are cards which have capacity less than 2GB and supports only sector > access mode then what's the solution? I am not sure If there are any such cards. > > Philip's patch handles both these scenarios effectively. > Can anyone mention the reason not taking Philip's patch into account, > which I feel is much > more fool proof than the implementation in mainline kernel > (http://www.mail-archive.com/linux-mmc@xxxxxxxxxxxxxxx/msg02307.html)? > > Thanks > Sujit > -- 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
