Am 2020-10-16 12:53, schrieb Ulf Hansson:
On Fri, 16 Oct 2020 at 01:12, Michael Walle <michael@xxxxxxxx> wrote:
On rare occations there is the following error:
mmc0: Tuning timeout, falling back to fixed sampling clock
There are SD cards which takes a significant longer time to reply to
the
first CMD19 command. The eSDHC takes the data timeout value into
account
during the tuning period. The SDHCI core doesn't explicitly set this
timeout for the tuning procedure. Thus on the slow cards, there might
be
a spurious "Buffer Read Ready" interrupt, which in turn triggers a
wrong
sequence of events. In the end this will lead to an unsuccessful
tuning
procedure and to the above error.
To workaround this, set the timeout to the maximum value (which is the
best we can do) and the SDHCI core will take care of the proper
timeout
handling.
Signed-off-by: Michael Walle <michael@xxxxxxxx>
Sound like this should be tagged for stable, right?
Yes, but I was unsure about that. I didn't find a lot of Fixes: tags in
the history of this driver (eg. for errata etc.)
I could repost a v2 with a fixes tag if you like.
-michael
