ahci sata data overruns

[Alan Cox]

On Thu, 08 Nov 2012 09:43:29 -0800
"Wolfgang S. Rupprecht" <wolfgang.rupprecht at gmail.com> wrote:

> 
> Can someone familiar with how the AHCI driver works confirm that data
> overruns on a SATA link can cause the driver to down-shift the SATA
> speed 6->3->1.5 Gbits/sec.  I don't see any kprintf's but I notice that
> a high speed SSD acting as if the SATA were running at 1.5 Gbits/sec.

It has a set of heuristics based upon error rate over time.

I'm not sure what you mean by "data overruns" however