Is anyone else using this brand? Any issues?
FWIW, the cards I have are 4GB and 8GB, Class 6 from newegg.com
Details of the issue are outlined on the linux-omap list:
http://marc.info/?l=linux-omap&m=129455305607155&w=2
Steve
The U-boot I am testing with uses 4 bit transfers, so that is not the issue.
I'll try to look at this more closely later this week when I receive
an mmc "extender" card so I can probe the power/signal lines, but I
suspect that it is perhaps related to one of the following:
- supply voltage setup. u-boot uses 3.0v, haven't checked linux. In another
thread Gerald suggests that the supply should be set to 3.15V
- timing setup differences between u-boot and linux
- introduction of write command - x-load/u-boot are read only
Steve
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The u-boot mmc driver sets the bus width/clock frequency based upon
the capabilities reported by the card.
You can see what settings u-boot is using with the mmcinfo command:
# mmcinfo
Device: OMAP SD/MMC
Manufacturer ID: 1d
OEM: 4144
Name: SD
Tran Speed: 25000000
Rd Block Len: 512
High Capacity: Yes
Capacity: 8069840896
Bus Width: 4-bit
The above settings are what is reported for the ADATA 8GB Class 6
card. IIRC, 25MHz and 4 bit was used for all of the cards I tested.
So it may well be that the kernel's 48Mhz @ 3.0V is too aggressive for
some cards.
Steve