[Shr-User] uSD hosed, on every unstable.

Gennady Kupava gb at bsdmn.com
Wed Sep 8 18:50:48 CEST 2010

В Срд, 08/09/2010 в 10:17 -0700, jeremy jozwik пишет:

> GTA02v6 # mmcinit
> Card Type:          SD 2.0 SDHC
> Manufacturer:       0x02, OEM "TM"
> Product name:       "SD08G", revision 3.8
> Serial number:      3226732165
> Manufacturing date: 5/2009
> MMC/SD size:        3MiB
> GTA02v6 #
> GTA02v6 # ext2ls mmc 0:1 /OSM
> cmd 0x10, arg 0x200 flags 0x15
> Error after cmd: 0xfffffffb
> bad MBR sector signature 0xeeee
> did not copy full output, sorry.

SD initalisation in kernel look strange and fact that we need
different rootwait/rootdelay in kernel, while u-boot can read
SD card almost instantly seriously puzzles me.

Also i can notice fact that I have 50% probability of successfull mmc
read in u-boot wuth 2-4-2 timings, while 4-4-4 is 100% successfull, may
be only in extremly rare cases. This makes me think that some delay (or
proper sync) is needed in mmc sequence.


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