2011/4/6 John Calixto <john.calixto@xxxxxxxxxxxxxx>: > On Tue, 5 Apr 2011, Andrei Warkentin wrote: >> Could you check the SD behavior for undefined ACMDs? If I do ACMD25, >> and ACMD25 is not defined, will it be executed as CMD25? This is the >> MMC behavior as I have mentioned. > The SD spec has a similar paragraph about unspecified ACMD opcodes - > they should be treated as the equivalent CMD opcodes. ÂHowever, all of > the opcodes that I listed are indeed specified. ÂSo, if the card > identifies itself as an SD card, it must implement those opcodes. ÂIf > it identifies itself as an SD card, and it does *not* implement the ACMD > opcodes I listed, then it likely "fell out the back door of the > manufacturing facility and landed on a store shelf" ;) ... its > quality/correct performance/reliability is unlikely. Not all specified ACMDs are mandatory. SD spec 2.00 says that only 6,13,41,42,51 are mandatory for all cards. This is less than the list you prepared in the patch. It's better not to make those exceptions and instead prepare an userspace daemon that opens mmcblkX (non-exclusively) and forwards the requests from unprivileged users to the device (or even implements application specific API). Best Regards, MichaÅ MirosÅaw -- 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
