Re: i2c and indirect vs. direct config

[Jason Thorpe <thorpej%me.com@localhost>]

> On Jun 1, 2018, at 3:45 PM, Paul Goyette <paul%whooppee.com@localhost> wrote:
> 
> On Thu, 31 May 2018, Jason Thorpe wrote:
> 
>> I spent some time reviewing NXP’s i2c spec this evening (well, during timeouts, etc. — GO DUBS), and I’m becoming convinced that there is a subtle error in our i2c_bitbang code… the spec seems pretty clear that a START-address-ACK should occur if a device is really there, and thus the “quick read” method for device detection should work 100% of the time. ...
> 
> There is at least one i2c bus controller that explicitly doesn't handle "quick" transactions - the imc controller built into the Intel X99 chip-set.  The docs are pretty clear that it implements an absolute minimum subset of i2c, just barely enough to talk to the SPD ROMs on memory DIMMs.

Ok, well, I’m open to suggestions about what should be done, here.  I’d like to get this situation resolved.

-- thorpej