Konstantin Kletschke wrote:
>> when ATAPI CHECK SENSE handling somehow failed to tell EH that it was an
>> exception not worth whining about.  Maybe EH action mask is not being
>> cleared properly?
> 
> Hmn, to take my pants down entirely: What is this "EH"?

libata EH == libatata exception handling.

> And how does the change of the .reset function affect this? May be, I
> will take a look onto this.

Your controller is raising exception continuously for some reason.
Have no idea yet.

Can you please apply the attached patch and post the resulting dmesg?

-- 
tejun