ASMedia 6201 AHCI boot failure

[Toru Nishimura <runqueue128%alkyltechnology.com@localhost>]

folks,

PLS forgive me if my trouble is well known and already solved so
far.  I'm having 6.1.5/amd64 boot failure with ASM6201 PCIe card
recently bought from eBay.

I found the similar trouble was once reported to netbsd-users@ around
2013-March with "wd0 dos error" subject.

/// short summary ///
When NB 6.1.5 is about to boot, kernel fails to detect a HGST 2.5
SATA drive attached with one of ASM port and goes a loop
complaining IO errrors.  Ubuntu Live DVD 14.04 has no issue (bootable,
able to do fdisk / mount) with the very same PC configuration.

/// excerpt of console message (hand typed) ///
wd0: <ST506>
wd0 at atabus1 drive 1
wd0: 69632 MB, 1024 ... <<< this seems incorrect
...
wd0: ahcisata0 port 1: device present, speed 1.5Gb/s
wd0: error reading fsbn 0 (wd0 bn 0; cn 0 tn 0 sn0), trying
wd0: (id not found)
...
wd0: dos partion I/O error
...

It seems communication errors are happening with the drive.

/// a bit background ///
When boot without a SATA drive, 6.1.5/amd64 has no trouble.  I
could see ASM AHCI in pcictl(8) output, but find not particulary
useful.

Poiters for the solution are welcome.

Toru Nishimura / ALKYL Technology