Re: Unhappy ahci controller on Dell XPS 13 9350

Hello, Andy.

On Tue, Jan 12, 2016 at 10:51:15PM -0800, Andy Lutomirski wrote:

Hi-

My XPS 13 9350 laptop has an nvme drive.  It has on-chip ahci
capability, but the M.2 port isn't using it due to the aforementioned
nvme drive using the same signal pins.

It is very unhappy:

[    0.230455] libata version 3.00 loaded.
[    1.039360] ahci 0000:00:17.0: version 3.0
[    1.039386] ahci 0000:00:17.0: forcing PORTS_IMPL to 0xff

...

It has Alpine Ridge, but I don't think there's such thing as SATA over
USB Type C.  I'd guess that that what's going on is that the ahci
controller genuinely has zero ports enabled and the workaround for
port_map == 0 is firing incorrectly.

Yeah, that's a workaround for very early ahci controllers.  I'll think
of a way to disable it for newer controllers.  Filtering on ahci
controller version should work.

Thanks.

-- 
tejun