On 20 August 2015 at 02:16, Barry Song [off-list ref] wrote:

2015-08-18 1:11 GMT+08:00 Ulf Hansson [off-list ref]:

quoted

On 11 August 2015 at 10:41, Barry Song [off-list ref] wrote:

quoted

From: Weijun Yang <redacted>

As SD Specifications Part1 Physical Layer Specification Version
3.01 says, CMD19 tuning is available for unlocked cards in transfer
state of 1.8V signaling mode. The small difference between v3.00
and 3.01 spec means that CMD19 tuning is also available for DDR50
mode.

So what happens with cards following the 3.0 spec version, those
doesn't need to support the tuning CMD right? Perhaps that needs to be
addressed in this patch well!?

from HW registers of the card, we cann't know whether the HW needs
tuning. it is said 3.0.x need tuning, but 3.0 doesn't need.  @weijun,
pls fix me if i am wrong.
if so, it seems we need a static flag somewhere to indicate whether
the tuning is needed. we can't detect to find the tuning requirement.

Another way is to always try doing the tuning for DDR50, but in case
of errors just ignore them and print a debug/info message!?

Kind regards
Uffe