Created attachment 423642 [details] .config used for both kernels Under 4.4.0 vanilla-sources, the mpt3sas driver recognizes SAS2008 PCI-Express Fusion-MPT SAS-2 just fine. Under 4.4.0-gentoo-r1 sources, it does not: *-storage UNCLAIMED description: Serial Attached SCSI controller product: SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon] The .config is attached.
This actually appears to be a bug in the vanilla kernel, now posted upstream as https://bugzilla.kernel.org/show_bug.cgi?id=111311