6.0-RC1 new message: "atapci0: failed to enable memory mapping!"

  I have a number of Dell Poweredge 750 servers here. Since upgrading them
to 6.0-RC1 (cvsup as of early on 10/21) from 5.4-STABLE, I'm getting a new
log message at boot time. Here's an extract:

atapci0: <Intel 6300ESB SATA150 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xfea0-0xfeaf at device 31.2 on pci0
atapci0: Reserved 0x10 bytes for rid 0x20 type 4 at 0xfea0
atapci0: failed to enable memory mapping!
ata0: <ATA channel 0> on atapci0
atapci0: Reserved 0x8 bytes for rid 0x10 type 4 at 0x1f0
atapci0: Reserved 0x1 bytes for rid 0x14 type 4 at 0x3f6
ata0: reset tp1 mask=03 ostat0=50 ostat1=00
ata0: stat0=0x00 err=0x01 lsb=0x14 msb=0xeb
ata0: stat1=0x00 err=0x04 lsb=0x00 msb=0x00
ata0: reset tp2 stat0=00 stat1=00 devices=0x4<ATAPI_MASTER>
ata0: [MPSAFE]
ata1: <ATA channel 1> on atapci0
atapci0: Reserved 0x8 bytes for rid 0x18 type 4 at 0x170
atapci0: Reserved 0x1 bytes for rid 0x1c type 4 at 0x376
ata1: reset tp1 mask=03 ostat0=80 ostat1=80
ata1: stat0=0x50 err=0x01 lsb=0x00 msb=0x00
ata1: stat1=0x50 err=0x01 lsb=0x00 msb=0x00
ata1: reset tp2 stat0=50 stat1=50 devices=0x3<ATA_SLAVE,ATA_MASTER>
ata1: [MPSAFE]

  The complete dmesg is here: http://www.tmk.com/transient/pe750-dmesg.txt

  This happens on a number of different configurations. The above dmesg is
from a box with a pair of SATA drives on the built-in SATA controller and a
CD-ROM on the ATA side of the controller; it also happens on a box with only
the CD-ROM (that system has SCSI disks).

  The message seems to be harmless, but is confusing.

  I searched the archives and didn't find any discussions relevant to this
problem on 6.0-RC1, so I'm posting here.

  I can provide remote access to the system (including BIOS console) to de-
velopers if needed.

        Terry Kennedy             http://www.tmk.com
        terry_at_tmk.com             New York, NY USA